St. John's wort extract with a high hyperforin content does not induce P-glycoprotein activity at the human blood-brain barrier

St. John's wort (SJW) extract, a herbal medicine with antidepressant effects, is a potent inducer of intestinal and/or hepatic cytochrome P450 (CYP) enzymes and P-glycoprotein (P-gp), which can cause clinically relevant drug interactions. It is currently not known whether SJW can also induce P-gp activity at the human blood-brain barrier (BBB), which may potentially lead to decreased brain exposure and efficacy of certain central nervous system (CNS)-targeted P-gp substrate drugs. In this study, we used a combination of positron emission tomography (PET) imaging and cocktail phenotyping to gain a comprehensive picture on the effect of SJW on central and peripheral P-gp and CYP activities. Before and after treatment of healthy volunteers (n = 10) with SJW extract with a high hyperforin content (3-6%) for 12-19 days (1800 mg/day), the activity of P-gp at the BBB was assessed by means of PET imaging with the P-gp substrate [11C]metoclopramide and the activity of peripheral P-gp and CYPs was assessed by administering a low-dose phenotyping cocktail (caffeine, omeprazole, dextromethorphan, and midazolam or fexofenadine). SJW significantly increased peripheral P-gp, CYP3A, and CYP2C19 activity. Conversely, no significant changes in the peripheral metabolism, brain distribution, and P-gp-mediated efflux of [11C]metoclopramide across the BBB were observed following the treatment with SJW extract. Our data suggest that SJW does not lead to significant P-gp induction at the human BBB despite its ability to induce peripheral P-gp and CYPs. Simultaneous intake of SJW with CNS-targeted P-gp substrate drugs is not expected to lead to P-gp-mediated drug interactions at the BBB.

Urticaria and angioedema as a prodromal cutaneous manifestation of SARS-CoV-2 (COVID-19) infection

This is a case of a patient who presented with an urticarial rash 48 hours before developing symptoms of fever and a continuous cough. She subsequently developed angioedema of her lips and hands before testing positive for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Urticarial rashes occurring 48 hours before other symptoms of COVID-19 infection have been documented. This case demonstrates the importance of heightened awareness that not all urticarial rashes represent spontaneous urticaria and as a consequence, this may result in misdiagnosis and ultimately delayed diagnosis. This is the first reported case in the literature of urticaria with angioedema as a prodromal phenomenon of COVID-19.

Oral H1 antihistamines as 'add-on' therapy to topical treatment for eczema

BACKGROUND

The symptoms of eczema can lead to sleeplessness and fatigue and may have a substantial impact on quality of life. Use of oral H1 antihistamines (H1 AH) as adjuvant therapy alongside topical agents is based on the idea that combining the anti-inflammatory effects of topical treatments with the blocking action of histamine on its receptors in the skin by H1 AH (to reduce the principal symptom of itch) might magnify or intensify the effect of treatment. Also, it would be unethical to compare oral H1 AH alone versus no treatment, as topical treatment is the standard management for this condition.

OBJECTIVES

To assess the effects of oral H1 antihistamines as 'add-on' therapy to topical treatment in adults and children with eczema.

SEARCH METHODS

We searched the following databases up to May 2018: the Cochrane Skin Group Specialised Register, CENTRAL, MEDLINE, Embase, and the GREAT database (Global Resource of EczemA Trials; from inception). We searched five trials registers and checked the reference lists of included and excluded studies for further references to relevant randomised controlled trials (RCTs). We also searched the abstracts of four conference proceedings held between 2000 and 2018.

SELECTION CRITERIA

We sought RCTs assessing oral H1 AH as 'add-on' therapy to topical treatment for people with eczema compared with topical treatment plus placebo or no additional treatment as add-on therapy.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methodological procedures. Primary outcome measures were 'Mean change in patient-assessed symptoms of eczema' and 'Proportion of participants reporting adverse effects and serious adverse events'. Secondary outcomes were 'Mean change in physician-assessed clinical signs', 'Mean change in quality of life', and 'Number of eczema flares'.

MAIN RESULTS

We included 25 studies (3285 randomised participants). Seventeen studies included 1344 adults, and eight studies included 1941 children. Most studies failed to report eczema severity at baseline, but they were conducted in secondary care settings, so it is likely that they recruited patients with more severe cases of eczema. Trial duration was between three days and 18 months. Researchers studied 13 different H1 AH treatments. We could not undertake pooling because of the high level of diversity across studies in terms of duration and dose of intervention, concomitant topical therapy, and outcome assessment. Risk of bias was generally unclear, but five studies had high risk of bias in one domain (attrition, selection, or reporting bias). Only one study measured quality of life, but these results were insufficient for statistical analysis.Although this review assessed 17 comparisons, we summarise here the results of three key comparisons in this review.Cetirizine versus placeboOne study compared cetirizine 0.5 mg/kg/d against placebo over 18 months in 795 children. Study authors did not report patient-assessed symptoms of eczema separately for pruritus. Cetirizine is probably associated with fewer adverse events (mainly mild) (risk ratio (RR) 0.68, 95% confidence interval (CI) 0.46 to 1.01) and the need for slightly less additional H1 AH use as an indication of eczema flare rate (P = 0.035; no further numerical data given). Physician-assessed clinical signs (SCORing Atopic Dermatitis index (SCORAD)) were reduced in both groups, but the difference between groups was reported as non-significant (no P value given). Evidence for this comparison was of moderate quality.One study assessed cetirizine 10 mg/d against placebo over four weeks in 84 adults. Results show no evidence of differences between groups in patient-assessed symptoms of eczema (pruritus measured as part of SCORAD; no numerical data given), numbers of adverse events (RR 1.11, 95% CI 0.50 to 2.45; mainly sedation, other skin-related problems, respiratory symptoms, or headache), or physician-assessed changes in clinical signs, amount of local rescue therapy required, or number of applications as an indicator of eczema flares (no numerical data reported). Evidence for this comparison was of low quality.Fexofenadine versus placeboCompared with placebo, fexofenadine 120 mg/d taken in adults over one week (one study) probably leads to a small reduction in patient-assessed symptoms of pruritus on a scale of 0 to 8 (mean difference (MD) -0.25, 95% CI -0.43 to -0.07; n = 400) and a greater reduction in the ratio of physician-assessed pruritus area to whole body surface area (P = 0.007; no further numerical data given); however, these reductions may not be clinically meaningful. Results suggest probably little or no difference in adverse events (mostly somnolence and headache) (RR 1.05, 95% CI 0.74 to 1.50; n = 411) nor in the amount of 0.1% hydrocortisone butyrate used (co-intervention in both groups) as an indicator of eczema flare, but no numerical data were given. Evidence for this comparison was of moderate quality.Loratadine versus placeboA study of 28 adults compared loratadine 10 mg/d taken over 4 weeks versus placebo. Researchers found no evidence of differences between groups in patient-assessed pruritus, measured by a 100-point visual analogue scale (MD -2.30, 95% CI -20.27 to 15.67); reduction in physician-assessed clinical signs (SCORAD) (MD -4.10, 95% CI -13.22 to 5.02); or adverse events. Study authors reported only one side effect (folliculitis with placebo) (RR 0.25, 95% CI 0.01 to 5.76). Evidence for this comparison was of low quality. Number of eczema flares was not measured for this comparison.

AUTHORS' CONCLUSIONS

Based on the main comparisons, we did not find consistent evidence that H1 AH treatments are effective as 'add-on' therapy for eczema when compared to placebo; evidence for this comparison was of low and moderate quality. However, fexofenadine probably leads to a small improvement in patient-assessed pruritus, with probably no significant difference in the amount of treatment used to prevent eczema flares. Cetirizine was no better than placebo in terms of physician-assessed clinical signs nor patient-assessed symptoms, and we found no evidence that loratadine was more beneficial than placebo, although all interventions seem safe.The quality of evidence was limited because of poor study design and imprecise results. Future researchers should clearly define the condition (course and severity) and clearly report their methods, especially participant selection and randomisation; baseline characteristics; and outcomes (based on the Harmonising Outcome Measures in Eczema initiative).

Efficacy and safety of bilastine in Japanese patients with perennial allergic rhinitis: A multicenter, randomized, double-blind, placebo-controlled, parallel-group phase III study

BACKGROUND

Bilastine, a novel non-sedating second-generation H₁ antihistamine, has been approved in most European countries since 2010. This study aimed to evaluate the superiority of bilastine over placebo in Japanese patients with perennial allergic rhinitis (PAR).

METHODS

This randomized, double-blind, placebo-controlled, parallel-group, phase III study (trial registration number JapicCTI-142600) evaluated the effect of a 2-week treatment period with bilastine (20 mg once daily), fexofenadine (60 mg twice daily), or a matched placebo (double dummy) in patients with PAR. All patients were instructed to record individual nasal and ocular symptoms in diaries daily. The primary endpoint was the mean change in total nasal symptom scores (TNSS) from baseline to Week 2 (Days 10-13).

RESULTS

A total of 765 patients were randomly allocated to receive bilastine, fexofenadine, or placebo (256, 254, and 255 patients, respectively). The mean change in TNSS from baseline at Week 2 was significantly decreased by bilastine (-0.98) compared to placebo (-0.63, P = 0.023). Bilastine and fexofenadine showed no significant difference in the primary endpoint. However, the mean change in TNSS from baseline on Day 1 was more significantly decreased by bilastine (-0.99) than by placebo (-0.28, P < 0.001) or fexofenadine (-0.62, P = 0.032). The active drugs also improved instantaneous TNSS 1 h after the first and before the second drug administration on Day 1 (P < 0.05). The study drugs were well tolerated.

CONCLUSIONS

After 2-week treatment period, bilastine 20 mg once daily was effective and tolerable in Japanese patients with PAR, and exhibited a rapid onset of action.

Histamine 1 Receptor Blockade Enhances Eosinophil-Mediated Clearance of Adult Filarial Worms

Filariae are tissue-invasive nematodes that cause diseases such as elephantiasis and river blindness. The goal of this study was to characterize the role of histamine during Litomosoides sigmodontis infection of BALB/c mice, a murine model of filariasis. Time course studies demonstrated that while expression of histidine decarboxylase mRNA increases throughout 12 weeks of infection, serum levels of histamine exhibit two peaks—one 30 minutes after primary infection and one 8 weeks later. Interestingly, mice treated with fexofenadine, a histamine receptor 1 inhibitor, demonstrated significantly reduced worm burden in infected mice compared to untreated infected controls. Although fexofenadine-treated mice had decreased antigen-specific IgE levels as well as lower splenocyte IL-5 and IFNγ production, they exhibited a greater than fourfold rise in eosinophil numbers at the tissue site where adult L. sigmodontis worms reside. Fexofenadine-mediated clearance of L. sigmodontis worms was dependent on host eosinophils, as fexofenadine did not decrease worm burdens in eosinophil-deficient dblGATA mice. These findings suggest that histamine release induced by tissue invasive helminths may aid parasite survival by diminishing eosinophilic responses. Further, these results raise the possibility that combining H1 receptor inhibitors with current anthelmintics may improve treatment efficacy for filariae and other tissue-invasive helminths.

Filariae are tissue-invasive parasitic roundworms that infect over 100 million people worldwide and cause debilitating conditions such as river blindness and elephantiasis. One of the major factors limiting our ability to eliminate these infections is the lack of drugs that kill adult worms when given as a short course therapy. Additionally, the mechanisms by which adult worms are cleared from infected individuals remains poorly understood. In this study, we demonstrate that treatment of infected mice with fexofenadine, an inhibitor of histamine receptor 1, significantly reduces adult worm numbers through a mechanism dependent on host eosinophils. These findings suggest that histamine release induced by parasitic worms may aid parasite survival by decreasing eosinophilic responses. Further, as antihistamines are generally safe medications, these results raise the possibility that antihistamine therapy may be useful either alone, or potentially in combination with other antifilarial medications such as diethylcarbamazine (DEC), to eliminate adult filarial worms from infected individuals.

Pruritic eruption on the chest

The fact that this patient's rash was limited to his chest provided an important diagnostic clue.

Exploring novel colon-targeting antihistaminic prodrug for colitis

Present work was inspired by an interesting finding of Raithel et al. (11) about remission of steroid-dependent, chronically active ulcerative colitis (UC) in a patient, after treatment with a combination of fexofenadine, disodium cromoglycate and an amino acid-based formula. Literature reports involvement of mast cells activation and increased histamine secretion in the pathogenesis of colitis. The purpose of present work was to evaluate the potential of a novel prodrug of fexofenadine in 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced colitis in rats. A colon-specific mutual amide prodrug of fexofenadine with D-glucosamine was synthesized. Release was studied in tissue homogenates and rat fecal matter by HPLC. It was further screened in TNBS-induced colitis in rats and also for adverse effects on rat liver, stomach and pancreas. The spectral analysis confirmed the structure of the prodrug. Highly hydrophilic prodrug enabled efficient delivery of fexofenadine to colon. Prodrug furnished negligible release of fexofenadine in upper gastrointestinal tract (GIT) homogenates. About 82% release of fexofenadine was observed in rat fecal matter at the end of 12 hours. The prodrug was twice as effective in lowering the quantifying parameters of colonic inflammation in TNBS- induced colitis than fexofenadine, D-glucosamine, their physical mixture and interestingly oral 5-amino salicylic acid while 2.7 times less effective than sulfasalazine. The prodrug restored disrupted colonic architecture to normal without adversely affecting stomach, liver and pancreas. In conclusion, the results support histamine involvement in the pathogenesis of UC. This novel, dual acting colon-specific prodrug of fexofenadine is promising as combination maintenance therapy with sulfasalazine for UC.

A randomized control trail of stepwise treatment with fluticasone propionate nasal spray and fexofenadine hydrochloride tablet for seasonal allergic rhinitis

BACKGROUND

In Japan, oral antihistamines are frequently used as the initial treatment for seasonal allergic rhinitis (SAR), and intranasal steroids are added when nasal symptoms worsen. This study aimed to evaluate whether starting treatment with fluticasone propionate nasal spray (FP) from the beginning of pollinosis symptoms and adding fexofenadine hydrochloride tablet (FEX) when SAR is aggravated could achieve improved amelioration of nasal symptoms throughout the pollen season in comparison with a treatment that involves starting with FEX and later adding FP.

METHODS

In this pragmatic, randomized, open-label, parallel-group trial, 51 Japanese cedar pollinosis patients (age, 16-85 years) were randomly divided and administered FP 100 mcg twice daily as an initial drug with FEX 60 mg twice daily as an additional drug and the same treatment in the reverse order. Nasal symptoms were evaluated in a daily dairy using a 4-point scale. The primary outcome was area under curve of the line representing the daily total nasal symptom score in the pollen season on a graph.

RESULTS

Initial treatment with FP was significantly (P = 0.0015) more effective than initial treatment with FEX in improving the primary outcome. The average daily total nasal symptom score in the initial treatment with FP group was better than that in the initial treatment with FEX group throughout the pollen season.

CONCLUSIONS

Initiating treatment with FP and adding FEX might lead to improved outcomes for nasal symptoms in comparison with the same drugs administered in the reverse order.

Urticaria due to antihistamines

H1-antihistamines are probably the most frequently used drugs in allergic diseases, with widely established efficacy, tolerance, and safety. We report a patient with urticaria due to ingestion of ebastine and fexofenadine. Skin prick tests, patch tests, and basophil activation tests with the implicated drugs and antihistamines from other families were negative. The oral challenges with the implicated antihistamines and other antihistamines tested were positive, but the patient tolerated an oral challenge with cetirizine. We present a patient with urticaria induced by different antihistamines in whom the diagnosis was established by oral challenge. The mechanism of sensitization remains unclear.

Preparation and evaluation of fexofenadine microemulsions for intranasal delivery

To enhance the solubility and bioavailability of poorly absorbable fexofenadine, microemulsion system composed of oil, surfactant and co-surfactant was developed for intranasal delivery. Phase behavior, particle size, viscosity and solubilization capacity of the microemulsion system were characterized. Histopathology and in vivo nasal absorption of the optimized microemulsion formulations were also investigated in rats. A single isotropic region was found in the pseudo-ternary phase diagrams developed at various ratios with Lauroglycol 90 as oil, Labrasol as surfactant and Plurol Oleique CC49 or its mixture with PEG-400 (1:1) as cosurfactant. An increase in the microemulsion region in pseudo-ternary phase systems was observed with increased surfactant concentration. The optimized microemulsion formulations showed higher solubulization of fexofenadine, i.e., F1 (22.64 mg/mL) and F2 (22.98 mg/mL), compared to its intrinsic water solubility (1.51 mg/mL). Nasal absorption of fexofenadine from these microemulsions was found to be fairly rapid. Tmax was observed within 5 min after intranasal administration at 1.0 mg/kg dose, and the absolute bioavailability (0-4 h) was about 68% compared to the intravenous administration in rats. Our results suggested that these microemulsion formulations could be used as an effective intranasal dosage form for the rapid-onset delivery of fexofenadine

Validation and application of a liquid chromatography-tandem mass spectrometric method for quantification of the drug transport probe fexofenadine in human plasma using 96-well filter plates

A rapid method to determine fexofenadine concentrations in human plasma using protein precipitation in 96-well plates and liquid chromatography-tandem mass spectrometry was validated. Plasma proteins were precipitated with acetonitrile containing the internal standard fexofenadine-d6, mixed briefly, and then filtered into a collection plate. The resulting filtrate was diluted and injected onto a Phenomenex Gemini C18 (50 mm x 2.0 mm, 5 microm) analytical column. The mobile phase consisted of 0.1% formic acid, 5 mM ammonium acetate in deionized water and methanol (35:65, v/v). The flow rate was 0.2 ml/min and the total run time was 2 min. Detection of the analytes was achieved using positive ion electrospray ionization and high resolution multiple reaction monitoring mode (H-SRM). The linear standard curve ranged from 1 to 500 ng/ml and the precision and accuracy (intra- and inter-run) were within 4.3% and 8.0%, respectively. The method has been applied successfully to determine fexofenadine concentrations in human plasma samples obtained from subjects administered a single oral dose of fexofenadine. The method is rapid, sensitive, selective and directly applicable to human pharmacokinetic studies involving fexofenadine.

Assessment of the antiobstructive effect of fexofenadine on nasal allergy challenge in patients with seasonal allergic rhinitis

The oral administration of fexofenadine 120 mg daily is a common treatment of seasonal allergic rhinitis (SAR). It reduces the H1 receptor-mediated symptoms, such as sneezing, pruritus, and nasal secretion as well as non-nasal symptoms such as conjunctivitis. The objective was to assess the effect of fexofenadine on nasal symptoms (such as nasal obstruction) in seasonal allergic rhinitis. A placebo-controlled, double-blind, randomized, cross-over study was performed which yielded evidence that two-week therapy with fexofenadine 120 mg daily in patients with SAR also relieves nasal obstruction and congestion. The parameters of nasal obstruction were evaluated by means of rhinoscopy, a subjective symptom score, and active anterior rhinomanometry. The subjective evaluation of nasal obstruction/congestion as recorded by the patient every 15 minutes for 4.5 hours after nasal allergen provocation showed a significant difference of the AUC (p = 0.025) between fexofenadine and placebo with a 12.8% lower obstruction after fexofenadine. The swelling of the nasal mucosa, which was assessed by rhinoscopy for 4.5 hours after nasal allergen provocation, was 21% lower after treatment with fexofenadine (p = 0.041). In this double-blind, placebo-controlled trial, subjective patient ratings as well as objective investigator assessments demonstrate the anti-obstructive effect of fexofenadine in nasal allergen challenge.

The Skin as a Target Organ for the Investigation of Antiallergic Drugs: Comparison between Cetirizine and Terfenadine

Two double-blind clinical pharmacology studies were performed in atopics in order to compare the inhibitory effects of cetirizine (CTZ) 2 HCl and terfenadine (TER) on histamine and antigen-induced skin reactions. In the first study, the subjects took single intakes of CTZ 10 mg and TER 60 mg. In the second study, they took CTZ 10 mg once a day and TER 60 mg b.i.d. for 3 weeks. CTZ was more effective than TER in inhibiting histamine skin reactivity. CTZ and TER were equally effective in inhibiting antigen-induced reactions. There was no tachyphylaxis, either for CTZ or for TER.

Suppression of histamine- and allergen-induced skin reactions: comparison of first- and second-generation antihistamines

BACKGROUND

Nonsedating antihistamines (nsAHs) are recommended as first-line therapeutics for the treatment of mast cell-driven disorders, including allergic rhinitis and urticaria. However, their superiority over first-generation AHs (fgAHs) has recently been called into question, mainly because of the lack of supporting head-to-head therapeutic studies.

OBJECTIVE

To compare the effects of 3 modem nsAHs with those of the fgAH hydroxyzine on histamine- and allergen-induced skin reactions in a controlled, double-blind, clinical trial.

METHODS

Skin prick tests with histamine and Dermatophagoides pteronyssinus extract were performed before and 4 hours after treatment with hydroxyzine, 25 mg; desloratadine, 5 mg; epinastine, 20 mg; fexofenadine, 120 mg; or placebo. Wheal and erythema development was evaluated by digital photography and planimetric analyses.

RESULTS

The nsAHs prevented the development of positive reactions to histamine in only 10% to 20% of all individuals tested (n = 75). In contrast, more than 50% of all hydroxyzine-treated individuals showed negative test reactions to histamine (ie, wheals <7 mm2 in area or <3 mm in diameter). Similar differences, although less pronounced, were detected when comparing the effects of nsAHs with hydroxyzine on D pteronyssinus prick testing in a limited number of D pteronyssinus-sensitized individuals.

CONCLUSIONS

These results indicate that hydroxyzine is more effective than nsAHs when given as recommended in suppressing histamine-induced or allergic skin reactions. Our results suggest that higher doses of nsAHs than those currently recommended are required for the treatment of skin responses to obtain antihistaminic and antiallergic effects that are equivalent to those of fgAHs.

Effects of pranlukast hydrate on airway hyperresponsiveness in non-asthmatic patients with Japanese cedar pollinosis

BACKGROUND

Recent studies have suggested that allergic rhinitis is closely related to bronchial asthma, reflecting the "one airway-one disease" hypothesis. It is unclear if the effects of pranlukast, a leukotriene-receptor antagonist, are consistent with this hypothesis.

OBJECTIVE

The goal of the study was to determine if pranlukast has effects on the upper and lower airways through a comparison of the effects of fexofenadine and pranlukast on airway hyperresponsiveness in non-asthmatic patients with cedar pollinosis before the Japanese cedar pollen season and during the peak pollen season.

METHODS

Patients received fexofenadine hydrochloride plus oral mequitazine (fexofenadine group) or pranlukast hydrate plus oral mequitazine (pranlukast group) as an initial treatment. Subsequent changes in airway responsiveness to acetylcholine were measured.

RESULTS

Among patients in whom coughing developed during the peak pollen season, airway responsiveness significantly increased in the fexofenadine group. In the pranlukast group, airway responsiveness did not increase significantly, regardless of the presence or absence of coughing.

CONCLUSIONS

The results indicate that pranlukast hydrate inhibits airway hyperresponsiveness in non-asthmatic patients with Japanese cedar pollinosis. In turn, this suggests that cysteinyl leukotrienes have a role in increased airway responsiveness.

Effects of fexofenadine on inflammatory mediators in nasal lavage fluid in intermittent allergic rhinitis

OBJECTIVE

Allergic rhinitis, a disease that impairs quality of life, is characterized by inflammation due to an allergic reaction. Fexofenadine is a second-generation histamine receptor blocker well known for its potent interaction with this inflammatory process. The main aim of this study was to further clarify the anti-inflammatory effects exerted by fexofenadine in patients with intermittent allergic rhinitis.

METHODS

Twenty patients with intermittent allergic rhinitis due to birch and mugwort pollen were enrolled. Fexofenadine was administered once a day at a dose of 120 mg. Clinical improvement was assessed by a symptom score, and nasal airway flows were measured by anterior rhinomanometry at baseline and after 2 weeks of treatment with fexofenadine. Nasal smears were tested for eosinophils and nasal lavage fluid were examined for histamine, cysteinyl leukotrienes, soluble intercellular adhesion molecule-1, eosinophil cationic protein, and albumin by enzyme-linked immunosorbent assay. All the tests were performed during the pollen season.

RESULTS

Fexofenadine induced a significant improvement in nasal and ocular symptoms (P < .001), nasal edema and secretion (P < .001), and nasal airway flow (P < .001). The clinical improvement was related to a significant reduction in all inflammatory mediators (P < .01 in all cases).

CONCLUSION

This study demonstrates that fexofenadine is able to mediate significant changes in different nasal lavage markers from patients with intermittent allergic rhinitis. The changes observed in the markers analyzed in both nasal secretions and serum are attributable to the anti-inflammatory effects of fexofenadine in vivo.

Evaluation of the efficacy and safety of olopatadine and fexofenadine compared with placebo in Japanese cedar pollinosis using an environmental exposure unit

BACKGROUND

Second-generation oral H1-antihistamines have become a mainstay of treatment for the symptoms of seasonal allergic rhinitis; however, the effect of olopatadine has not been widely reported to date.

OBJECTIVES

To evaluate the efficacy of 2 oral H1-antihistamines, olopatadine and fexofenadine, in the treatment of the nasal symptoms of Japanese cedar pollinosis and their possible side effects.

METHODS

This was a randomized, double-blind, placebo-controlled, crossover study conducted in an environmental exposure unit (EEU). Twenty volunteers suffering from Japanese cedar pollinosis were randomly divided into 3 groups and exposed to cedar pollen in the EEU with oral administration of olopatadine hydrochloride (5 mg), fexofenadine hydrochloride (60 mg), or placebo 1 hour prior to pollen exposure. Nasal symptoms, activity impairment, and subjective sleepiness were self-assessed during the study period. Attention was measured using the digit cancellation test. The trial was repeated after 4 and 7 weeks.

RESULTS

Compared with placebo, olopatadine significantly improved nasal symptoms and activity impairment during pollen exposure (P < .05). There was no significant relief of nasal discharge or nasal congestion with fexofenadine throughout the 5-hour exposure to cedar pollen. Furthermore, olopatadine significantly reduced nasal congestion during the first 2 hours, as well as sneezing and nasal discharge 4 hours after admission to the EEU compared with fexofenadine (P < .05). There was no significant difference in the effect on subjective sleepiness among the 3 groups, and all 3 agents had little effect on attention.

CONCLUSIONS

These findings suggest that olopatadine is more effective than placebo and fexofenadine in improving nasal symptoms of Japanese cedar pollinosis.

Suppressive activity of fexofenadine hydrochloride on nitric oxide production in-vitro and in-vivo

The aim of this study was to examine the effect of fexofenadine hydrochloride (FEX), a histamine H1-receptor antagonist, on nitric oxide (NO) production in-vitro and in-vivo. Nasal fibroblasts (5 x 10(5) cells per mL) were stimulated with 25 ng mL(-1) tumour necrosis factor-alpha in the presence of various concentrations of FEX. NO levels in 24-h-culture supernatants were measured by the Griess method and levels of inducible nitric oxide synthase (iNOS) mRNA levels in 12-h-cultured cells were measured by ELISA. FEX at more than 0.5 microg mL(-1) suppressed NO production from fibroblasts by inhibiting expression of iNOS mRNA. We also examined whether FEX could suppress NO production induced by lipopolysaccharide (LPS) stimulation in-vivo. BALB/c mice were treated with 5.0 mg kg(-1) LPS i.p. after daily oral doses of FEX, 1.0 mg kg(-1), for 1-3 weeks. Plasma was obtained 6 h later and NO levels measured by the Griess method. Expression of iNOS mRNA in lung tissues was measured by ELISA 6 h after LPS injection. Oral administration of FEX for 2 and 3 weeks, but not 1 week, significantly suppressed NO levels in plasma through the inhibition of iNOS mRNA expression, which were enhanced by LPS stimulation. These results suggest that the attenuating effect of FEX on NO production may be of therapeutic benefit in allergic diseases.

Microdose clinical trial: Quantitative determination of fexofenadine in human plasma using liquid chromatography/electrospray ionization tandem mass spectrometry

A sample treatment procedure and high-sensitive liquid chromatography/electrospray ionization tandem mass spectrometry (LC/ESI-MS/MS) method for quantitative determination of fexofenadine in human plasma was developed for a microdose clinical trial with a cold drug, i.e., a non-radioisotope-labeled drug. Fexofenadine and terfenadine, as internal standard, were extracted from plasma samples using a 96-well solid-phase extraction plate (Oasis HLB). Quantitation was performed on an ACQUITY UPLC system and an API 5000 mass spectrometer by multiple reaction monitoring. Chromatographic separation was achieved on an XBridge C18 column (100 mm x 2.1 mm i.d., particle size 3.5 microm) using acetonitrile/2 mM ammonium acetate (91:9, v/v) as the mobile phase at a flow rate of 0.6 ml/min. The analytical method was validated in accordance with the FDA guideline for validation of bioanalytical methods. The calibration curve was linear in the range of 10-1000 pg/ml using 200 microl of plasma. Analytical method validation for the clinical dose, for which the calibration curve was linear in the range of 1-500 ng/ml using 20 microl of plasma, was also conducted. Each method was successfully applied for making determinations in plasma using LC/ESI-MS/MS after administration of a microdose (100 microg solution) and a clinical dose (60 mg dose) in eight healthy volunteers.

Laser ablation electrospray ionization for atmospheric pressure, in vivo, and imaging mass spectrometry

Mass spectrometric analysis of biomolecules under ambient conditions promises to enable the in vivo investigation of diverse biochemical changes in organisms with high specificity. Here we report on a novel combination of infrared laser ablation with electrospray ionization (LAESI) as an ambient ion source for mass spectrometry. As a result of the interactions between the ablation plume and the spray, LAESI accomplishes electrospray-like ionization. Without any sample preparation or pretreatment, this technique was capable of detecting a variety of molecular classes and size ranges (up to 66 kDa) with a detection limit of 8 and 25 fmol for verapamil and reserpine, respectively, and quantitation capabilities with a four-decade dynamic range. We demonstrated the utility of LAESI in a broad variety of applications ranging from plant biology to clinical analysis. Proteins, lipids, and metabolites were identified, and antihistamine excretion was followed via the direct analysis of bodily fluids (urine, blood, and serum). We also performed in vivo spatial profiling (on leaf, stem, and root) of metabolites in a French marigold (Tagetes patula) seedling.

Comparison of the QT interval response during sinus and paced rhythm in conscious and anesthetized beagle dogs

INTRODUCTION

The aim of the present study was to compare sensitivity in detecting the drug-induced QT interval prolongation in three dog models: conscious telemetered at sinus rhythm and conscious and anesthetized dogs during atrial pacing. The test substances used represent different chemical classes with different pharmacological and pharmacokinetic profiles.

METHOD

Dofetilide and moxifloxacin were tested in all models, whereas cisapride and terfenadine were tested in the conscious telemetered and paced models. All substances were given as two consecutive 1.5-h intravenous infusions (infusions 1 and 2). The individual concentration-time courses of dofetilide, moxifloxacin, and cisapride were linked to the drug-induced effects on the QT interval and described with a pharmacokinetic-pharmacodynamic model to obtain an estimate of the unbound plasma concentrations at steady state that give a 10- and 20-ms drug-induced QT interval prolongation (CE10ms and CE20ms).

RESULTS

In the conscious telemetered, conscious paced, and anesthetized dog models, the mean CE10ms values were 1.4, 4.0, and 2.5 nM for dofetilide and 1300, 1800, and 12,200 nM for moxifloxacin. For cisapride, the CE10ms values were 8.0 and 4.4 nM in the conscious telemetered and conscious paced dog models. The drug-induced QT interval prolongation during the last 30 min of infusions 1 and 2 was comparable in the conscious models, but smaller in the anesthetized dog model. Terfenadine displayed a marked delay in onset of response, which could only be detected by the extended ECG recording.

DISCUSSION

All dog models investigated detected QT interval prolongation after administration of the investigated test substances with similar sensitivity, except for a lower sensitivity in the anesthetized dogs following moxifloxacin administration. The conscious telemetered dog model was favorable, mainly due to the extended continuous ECG recording, which facilitated detection and quantification of delayed temporal differences between systemic exposure and drug-induced QT interval prolongation.

Evaluation of the guinea pig monophasic action potential (MAP) assay in predicting drug-induced delay of ventricular repolarisation using 12 clinically documented drugs

INTRODUCTION

While the dog in vivo model is commonly employed in the later phase of discovery for assessing drug-induced QT prolongation, an early screening assay is valuable when selecting compounds for further development and when compound availability usually is low. One such screening assay is the anaesthetised guinea pig monophasic action potential (MAP) model. The aim of the present study was to evaluate the ability of this model to detect proarrhythmic properties by testing a set of reference compounds with known clinical profile. Moreover, these results were compared to data previously obtained using in vivo canine QT assays (QT PRODACT study).

METHODS

Anaesthetised and ventilated male guinea pigs were vagotomised and pretreated with propranolol. After thoracotomy, a pacing electrode was clipped to the left atrial appendage and a suction MAP electrode positioned on the left ventricular epicardium. The drug or corresponding vehicle was injected intravenously in cumulative doses and MAP duration at 90% repolarisation (MAPD90) was recorded during cardiac pacing.

RESULTS

The 8 drugs known to be proarrhythmic in the clinic all displayed dose-dependent prolongation of MAPD90, while the 4 drugs devoid of dysrhythmia in man had no effect. When comparing doses producing a 10% MAPD90 increase with doses reported to increase QTc by 10% in dogs a strong correlation was seen (R(2) 0.94 and 0.58 for anaesthetised and conscious dogs, respectively).

DISCUSSION

The guinea pig MAP assay identified all clinically positive drugs while negative drugs were without effect on ventricular repolarisation. Furthermore, a good concurrence is shown between the guinea pig and dog models in identifying compounds with proarrhythmic properties. Overall, the study reinforces the anaesthetised guinea pig MAP model as a reliable assay predicting QT liability of new chemical entities and as a highly sensitive early screening model for cardiovascular risk.

BIOEQUIVALENCE OF TWO FEXOFENADINE FORMULATIONS IN HEALTHY HUMAN VOLUNTEERS AFTER SINGLE ORAL ADMINISTRATION

AIM

A randomized, two-way, crossover, bioequivalence study was conducted in 25 fasting, healthy, male volunteers to compare two brands of fexofenadine 180 mg tablets, FEXOFENADINE 180 mg Film Tablet (Drogsan A.S., Ankara, Turkey) as test and Telfast 180 mg Tablet (Aventis Pharma, Frankfurt am Main, Germany) as a reference product.

METHOD

One tablet of either formulation was administered after 10 h of overnight fasting. After dosing, serial blood samples were collected during a period of 48 hours. Plasma samples were analysed for fexofenadine by a validated HPLC method. The pharmacokinetic parameters AUC(0-48), AUC(0-alpha), C(max), T(max), K(el), T(1/2), and CL were determined from plasma concentration-time profiles for both formulations and were compared statistically.

RESULTS AND CONCLUSIONS

The analysis of variance (ANOVA) did not show any significant difference between the two formulations and 90% confidence intervals (CI) fell within the acceptable range, satisfying the bioequivalence criteria of the FDA. Based on these statistical inferences it was concluded that the two brands exhibited comparable pharmacokinetics profiles and that Drogsan's Fexofenadine is equivalent to Telfast of Aventis Pharma, Frankfurt am Main, Germany.

Onset of action of fexofenadine hydrochloride 60 mg/pseudoephedrine hydrochloride 120 mg in subjects aged 12 years with moderate to severe seasonal allergic rhinitis: a pooled analysis of two single-dose, randomized, double-blind, placebo-controlled allergen exposure unit studies

BACKGROUND

The onset of action of antihistamine-decongestant combinations is an important factor in the treatment of subjects with seasonal allergic rhinitis (SAR).

OBJECTIVE

This was a pooled analysis of 2 published studies with identical designs investigating the onset of action of the combination of fexofenadine hydrochloride 60 mg/pseudoephedrine hydrochloride 120 mg (FEX60/PSE120) in subjects with moderate to severe SAR.

METHODS

Subjects aged 12 years received single doses of FEX60/PSE120 or placebo in 2 randomized, double-blind, placebo-controlled, parallel-group, allergen exposure unit studies and recorded their SAR symptoms on diary cards before dosing, at 15-minute intervals for 2 hours after dosing, and at 30-minute intervals for the next 4 hours. The primary efficacy end point was onset of action, assessed in terms of absolute change in the major symptom complex (MSC) score, which was the sum of scores for the individual symptoms of stuffy nose, itchy nose, runny nose, watery eyes, itchy eyes, itchy ears/throat, and sneezing. Secondary end points included the absolute and percent change in the total symptom complex (TSC) score (the sum of the MSC score plus the scores for nose blowing, sniffles, postnasal drip, and cough) and individual symptom scores. Treatment-emergent adverse events (TEAEs) were recorded. Analyses were performed on the modified intention-to-treat (mITT) population, which included all subjects who were randomized to treatment and took the single dose of study medication according to the protocol.

RESULTS

A total of 1693 subjects were screened in the 2 studies, and 786 were randomized (298 in study 1, 488 in study 2). Two subjects withdrew from study 2; therefore, the mITT population consisted of 784 subjects. Subjects' mean age was 33.4 years, and 64.4% were female. The onset of action of FEX60/PSE120 was 45 minutes; the least squares mean (SD) treatment difference in the change from baseline in absolute MSC score was 0.8 (0.31) (95% CI, 0.2-1.4; P = 0.008). All subsequent changes from baseline in MSC scores were statistically significant for FEX60/PSE120 compared with placebo (P < 0.001). The absolute and percent change in TSC score and the percent change in MSC score were significantly decreased at all time points from 45 minutes after dosing for FEX60/PSE120 compared with placebo (all, P < 0.05). Individual symptoms (mean of hours 1 to 5) also were significantly improved with FEX60/PSE120 compared with placebo (all, P < 0.05). TEAEs were reported by 2.3% (9/391) and 4.3% (17/393) of subjects receiving FEX60/PSE120 and placebo, respectively. The most commonly occurring TEAS in the FEX60/PSE120 and placebo groups was somnolence (n = 4 and n = 6, respectively).

CONCLUSION

In this pooled analysis of 2 allergen exposure unit studies, FEX60/PSE120 had an onset of action of 45 minutes and a sustained effect throughout the 6-hour study period in subjects with moderate to severe SAR.

The effect of fexofenadine hydrochloride on productivity and quality of life in patients with chronic idiopathic urticaria

The present study examined the impact of once-daily fexofenadine hydrochloride (HCl) 180 mg on health-related quality of life (HRQL) in subjects with chronic idiopathic urticaria (CIU). This was a multicenter, randomized, double-blind. parallel-group, placebo-controlled study. Subjects completed the Dermatology Life Quality Index (DLQI) and the Work Productivity and Activity Impairment (WPAI) questionnaire at baseline and at weeks 2 and 4. The primary HRQL end point was mean change from baseline to week 4 in total DLQI score. Subjects in the fexofenadine HCl treatment group (n = 163) experienced significantly greater improvements in mean total DLQI score (P = .0219) and in the individual domains of symptoms and feelings (P = .0119) and personal relationships (P = .0091) compared with those in the placebo group (n = 91). Subjects who received fexofenadine HCl experienced less work productivity impairment, overall work impairment, and activity impairment than those who received placebo. The results indicated that once-daily fexofenadine HCl 180 mg improved the HRQL of subjects with CIU, as assessed by change in total DLQI score.

QT prolongation in guinea pigs for preliminary screening of torsadogenicity of drugs and drug-candidates. II

Experimental approaches on anaesthetised guinea pigs have been shown recently to be satisfactorily predictive of the torsadogenic risk of drugs. This work aimed at obtaining additional data, for a further understanding of the reliability and/or the limits of this model. Clonidine (non-torsadogenic in humans) induced a lengthening of the ECG parameter of RR in anaesthetised guinea pigs, without any corresponding increase of QT (corrected by the algorithms of Bazett and Fridericia). Thus, 'QT correct' prolonging effects produced by drugs torsadogenic in humans, on the guinea pig model are primarily due to inhibition of cardiac repolarisation. The corresponding RR prolongation is a consequence (not the cause) of this primary effect. Astemizole, haloperidol and terfenadine, torsadogenic in humans, produced in Langendorff perfused guinea pig hearts a prolongation of the QT interval. Chlorprotixene (non-torsadogenic) did not produce any significant effect on QT. These results are fully consistent with previous observations in anaesthetised guinea pigs. In Langendorff perfused hearts, pentobarbital does not affect cardiac repolarisation and does not potentiate the QT-prolonging effect of astemizole. Together with the findings reported by many authors, these data suggest that ECG recording in anaesthetised guinea pigs is a reliable model for cardiac safety studies evaluating the influence of drugs on the repolarisation process.

Influences of Histamine H1 Receptor Antagonists on Maximal Electroshock Seizure in Infant Rats

The influences of histamine H1 receptor antagonists on maximal electroshock seizure were studied using infant rats. In this study, electroconvulsion was induced by stimulating rats using ear-clip electrodes, and the durations of electroencephalogram (EEG) seizure, tonic extensor (TE) seizure and clonic (CL) seizure induced by maximal electroshock were measured. Diphenhydramine, chlorpheniramine, cyproheptadine and ketotifen caused a dose-dependent and significant prolongation of both EEG seizure and TE seizure induced by maximal electroshock. On the other hand, epinastine and fexofenadine caused no such effects, even at a dose of 50 mg/kg. All drugs used in this study showed no significant effect on CL seizure induced by maximal electroshock. From these findings, it is suggested that epinastine and fexofenadine may cause no harmful influence on epilepsy, even when used in a little child.

Reduction of repolarization reserve by halothane anaesthesia sensitizes the guinea-pig heart for drug-induced QT interval prolongation

The utility of halothane-anaesthetized guinea-pigs as an in vivo model for predicting the clinical potential of a drug to induce QT interval prolongation was assessed using the electrocardiogram and monophasic action potential (MAP) recordings with electrical ventricular pacing. Intravenous administration of D-sotalol (0.3 mg kg(-1)) and terfenadine (0.3 mg kg(-1)), blockers of a rapid component of delayed rectifier potassium currents, prolonged the QT interval by 32+/-7 and 23+/-6 ms, respectively, whereas chromanol 293B (1 mg kg(-1)), a blocker of a slow component of delayed rectifier potassium currents, lengthened it by 33+/-8 ms. The extent of the QT interval prolongation by these drugs was greater than those in previous reports using pentobarbital-anaesthetized guinea-pigs. The MAP duration at the control was shortened by decreasing the pacing cycle length from 400 to 200 ms, but the MAP duration at each cycle length was prolonged by D-sotalol. The formulas of Van de Water, Matsunaga, Fridericia and Bazett showed good correlation of the repolarization period when compared with the MAP duration at a pacing cycle length of 400 ms. The halothane-anaesthetized guinea-pig model may possess enough sensitivity to detect drug-induced QT interval prolongation, indicating that halothane anaesthesia can reduce the repolarization reserve of the heart in vivo.

Time-dependent interaction between lopinavir/ritonavir and fexofenadine

This study investigated the effect of single-dose and steady-state lopinavir/ritonavir on the exposure to fexofenadine, as a measure of P-glycoprotein activity. Sixteen volunteers (8 women) received single-dose oral fexofenadine 120 mg alone, in combination with single-dose ritonavir 100 mg or lopinavir/ritonavir 400/100 mg (randomized 1:1, stratified by sex), and in combination with steady-state lopinavir/ritonavir 400/100 mg twice daily. Single-dose ritonavir and lopinavir/ritonavir increased the area under the fexofenadine plasma concentration-time curve from 0 to infinity (AUC(infinity)) by 2.2- and 4.0-fold, respectively (P < .02). Steady-state lopinavir/ritonavir increased the fexofenadine AUC(infinity) by 2.9-fold. No changes were observed in the fexofenadine elimination half-life (P > .12). The fexofenadine AUC(infinity) was increased by lopinavir/ritonavir, likely due to increased bioavailability secondary to P-glycoprotein inhibition. After repeated administration of lopinavir/ritonavir, the interaction was attenuated compared to the single-dose effect, although a net inhibitory effect was maintained. Time-dependent inhibition of P-glycoprotein by lopinavir/ritonavir should be considered when P-glycoprotein substrates are coadministered.

[The effect of 5-days of cetirizine, desloratadine, fexofenadine 120 and 180 mg, levocetirizine, loratadine treatment on the histamine-induced skin reaction and skin blood flow--a randomized, double-blind, placebo controlled trial]

THE AIM

of this study was to compare the effect of the following antihistamines: cetirizine 10mg, desloratadine 5mg, fexofenadine 120 and 180mg, levocetirizine 5mg, loratadine 10mg, and placebo, administered in the recommended doses over the period of 5 days, on the visually assessed histamine-induced skin reaction, using the Laser Doppler flowmetry (LDF).

MATERIAL AND METHODS

Forty two volunteers (aged 18-22) who gave a written consent before entering the study, were randomized in seven groups of six subjects each. The skin prick test with histamine solution of 10mg/ml was performed on the ventral forearm, 10 cm from the elbow, before and at 2, 4, 6, 8, 10, 12, 18, and 24 hours after drug administration, as well as once daily for the next 4 days of antihistamine drug or placebo intake, and 9 days following the treatment. Diameters of wheal and flare as well as the LDF index measured with Periflux PF3 flowmeter and skin probe, 5mm from the histamine-provoked area, were assessed 10 minutes after performing the above-mentioned skin prick test.

RESULTS

The current study revealed that during the 5-day treatment with recommended doses of cetirizine, desloratadine, fexofenadine, levocetirizine, and loratadine, a significant reduction of histamine-induced wheal, flare and the LDF index was observed as compared to the initial values and placebo intake, reaching the maximum value within the first 24 hours, weakening on the next day, and then gradually increasing during the following days. After the 5-day treatment drugs used for the study were lined up according to the volume of reduction in histamine-induced skin reaction (largest>smallest): levocetirizine > cetirizine > fexofenadine 180mg = fexofenadine 120mg > loratadine = desloratadine.

CONCLUSIONS

Following the end of the treatment, the effect of the antihistamines on skin reaction was subsiding in such an order: after 24 hours in case of loratadine and desloratadine, after two days for both doses of fexofenadine, and 3-4 days for cetirizine and levocetirizine.

[Inhibition of histamine-induced wheel after a recommended single dose administration of 10 mg cetirizine, 5 mg desloratadine, 120 i 180 mg fexofenadine, 5 mg levocetirizine and 10 mg loratadine--a randomized, double-blind, placebo controlled trial]

OBJECTIVE

The aim of the study was to compare the effect of inhibition skin reactivity after administration of single dose administration of various second generation antihistamines in the healthy people group.

MATERIAL AND METHODS

Forty two healthy subjects (aged 22+/-18 years) were randomized into seven groups which received orally: cetirizine 10 mg, loratadine 10 mg, desloratadine 5 mg, levocetirizine 5 mg, fexofenadne 120 mg and 180 mg, or placebo respectively. The skin microcirculation reaction after 10 mg/ml histamine administration was estimated visually on the forearm (diameter of wheal and flare) and by Laser Doppler flowmetry before and after study drug or placebo administration prior and, 2, 4, 6, 8, 10, 12, 18, 24 h and one time daily every next 9 days.

RESULTS

There were significant differences of histamine-induced wheal, flare and skin blood flow inhibition vs baseline and placebo after drug administration. There were different dyr'mmics in suppression effect after histamine-induced skin reactivity in various drug groups. The overall inhibitory potency was statistically higher for cetirizine, levocetirizine and fexofenadine (even 95% ve basline) as compared to loratadine and desloratadine (even 65% vs basline). Different times of retreated inhibition effect after administered drugs were observed.

CONCLUSIONS

The study drugs shown significant different dynamics of skin reaction inhibition vs baseline and placebo. There were observed strongest effect after levocetirizine and cetirizine and next order after fexofenadine, desloratadine and loratadine.

Altered oral bioavailability and pharmacokinetics of P-glycoprotein substrates by coadministration of biochanin A

Effects of coadministration of dietary supplement biochanin A (BA) on the pharmacokinetics of three P-glycoprotein substrates, paclitaxel, digoxin, and fexofenadine, were investigated in rats. With BA coadministration, the oral bioavailability and peak plasma concentration were markedly increased by 3.77- and 2.04-fold for paclitaxel, 1.75- and 1.71-fold for digoxin, but were reduced by 0.694- and 0.429-fold for fexofenadine, respectively. Paclitaxel is a Pgp and CYP3A substrate, the drastic increase in systemic exposure may be attributed to the synergistic inhibition of Pgp and CYP3A by BA in the intestine. Digoxin is a substrate for Pgp, CYP3A, and Oatp2. BA may suboptimally inhibit Pgp and CYP3A, resulting in a moderate increase in oral bioavailability of digoxin. Fexofenadine is a substrate for Pgp, Oatp1, Oatp2, and Oatp3. BA appears to preferentially inhibit Oatp3 over Pgp in the intestine, leading to the decreased oral absorption of fexofenadine. No significant changes in mean residence time and terminal half-life were observed for all drugs, suggesting a negligible effect of BA on their hepatic/renal elimination. These findings demonstrate the importance of interplay among uptake/efflux transporters and metabolizing enzymes. The enhanced oral absorption by BA coadministration may be exploited to improve oral bioavailability of Pgp and CYP3A substrate compounds.

Efficacy and central nervous system impairment of newer-generation prescription antihistamines in seasonal allergic rhinitis

Allergic rhinitis is a highly prevalent disorder and oral antihistamines are often used to manage patient symptoms. Older-generation antihistamines, such as diphenhydramine and chlorpheniramine, are effective at relieving the symptoms of seasonal allergic rhinitis (SAR); however, they are associated with adverse events, including sedation and impairment, at, or above, the recommended dose. Newer-generation antihistamines, such as desloratadine, cetirizine and fexofenadine, were developed to minimize adverse events. In this article, studies examining newer-generation antihistamines in adults and children were reviewed. The clinical evidence confirms that desloratadine, cetirizine and fexofenadine are effective at managing the symptoms of SAR in adults and children; however, cetirizine is more likely to cause sedation. Physician intervention is paramount to SAR symptom management. It is essential that appropriate treatment relieves SAR symptoms with absent or minimal adverse events. This is particularly important for those patients involved in skilled and cognitive activities or safety-critical jobs.

Allergy medication in Japanese volunteers: treatment effect of single doses on nocturnal sleep architecture and next day residual effects

OBJECTIVES

To evaluate the acute effects of two histamine H(1)-receptor antagonists on nocturnal sleep architecture and on next day cognitive function and psychomotor performance.

METHODS

This was a single-site, randomized, double-blind, 3-way crossover study, comparing the effects of a single dose of chlorpheniramine (6 mg), fexofenadine (120 mg) and placebo in 18 healthy (male and female) Japanese volunteers aged 20-55 years. Volunteers were resident for 3 days and each period was separated by a minimum 5-day washout period. The three treatments were administered at 23.00 h. Overnight sleep was measured from 23.00 h to 07.00 h using polysomnography. Residual effects were studied at 07.00 h and 9.00 h the next morning, with the latency to sleep (sleep latency test) measured at 09.30 h.

RESULTS

Compared with placebo, chlorpheniramine increased the latencies to sleep onset and rapid eye movement (REM) sleep (p < or = 0.05 for both), and reduced the duration of REM sleep (p <or= 0.01), but this was not observed with fexofenadine. As far as residual effects the next morning were concerned there were decrements in performance with chlorpheniramine, but not with fexofenadine. Chlorpheniramine 6 mg impaired divided attention (p < 0.001), vigilance (p < 0.05), working memory (p < 0.0001) and sensori-motor performance (p < 0.01), and the latency to daytime sleep was reduced (p < 0.0001). Six adverse events possibly related to study medication were reported during the study, three of which were related to placebo, two to fexofenadine and one to chlorpheniramine.

CONCLUSION

These findings suggest that a single nocturnal dose of fexofenadine has advantages over the first-generation antihistamine chlorpheniramine, being free of disruption of night-time sleep and detrimental effects on cognitive performance the next day. It is likely that this advantage will remain with chronic ingestion, but this would need to be confirmed.

Practical application of guinea pig telemetry system for QT evaluation

The purpose of this study was to evaluate a telemetry system for examining QT evaluation in the conscious free-moving guinea pig using 10 reference compounds whose effects on human QT interval are well established: 8 positive references (bepridil, terfenadine, cisapride, haloperidol, pimozide, quinidine, E-4031 and thioridazine), and 2 negative references (propranolol and nifedipine). Pharmacokinetic experiments were also performed for the 8 positive references. Telemetry transmitters were implanted subcutaneously in male Hartley guinea pigs, and the RR and QT intervals were measured. All 8 positive references prolonged QTc (QTc = k x QT/RR(1/2)) 10% or more during the 60 min observation period. When the values of the QTc changes were plotted against the serum concentrations, the resulting curves exhibited an anticlockwise hysteresis loop for all 8 references. In guinea pigs treated with haloperidol, changes of the T-wave shape from positive to flat were observed. The 2 negative references did not prolong the QTc. These findings suggest that the present telemetry guinea pig model is useful for QT evaluation in the early stages of drug development, because of the small body size of guinea pigs and their action potential configuration, which is similar to that of humans.

Effect of erythromycin on the absorption of fexofenadine in the jejunum, ileum and colon determined using local intubation in healthy volunteers

OBJECTIVE

To investigate the in vivo intestinal absorption mechanism(s) and systemic availability of fexofenadine in the jejunum, ileum and colon in humans.

METHOD

A single dose of fexofenadine hydrochloride (60 mg as solution) was applied under fasting conditions, either alone or directly after a solution of erythromycin lactobionate (corresponding to a dose of 250 mg erythromycin), to the jejunum, ileum and colon in 6 healthy volunteers (3 male and 3 female) using a regional intubation dosing technology (Bioperm AB, Lund, Sweden). A total of 36 fexofenadine administrations were performed. The administration of fexofenadine to the specified location either alone or in combination with erythromycin was conducted in a randomized manner on 2 consecutive days with a 5-day washout period between doses.

RESULTS

The plasma AUC for fexofenadine (mean +/- SEM) was higher (2.7-to 2.3-fold, p < 0.001) after application to the jejunum (1090 +/- 134 h x ng/ml) than to the ileum (404 +/- 102 h x ng/ml) or colon (476 +/- 212 h x ng/ml). No significant differences were found between application to the ileum and colon. The administration of erythromycin affected the absorption rate after jejunal application with a prolonged tmax from a median of 40 min (range 10-90 min) to a median of 3 hours (range 10-180 min) (p = 0.009). A change in tmax was not observed with application to the ileum and colon. The concomitant administration of erythromycin in the jejunum tended to increase the plasma AUC of fexofenadine from 1090 +/- 134 to 1750 +/- 305 h x ng/ml (p = 0.069).

CONCLUSIONS

The systemic availability of fexofenadine was significantly higher after jejunal administration in accordance with a low permeability compound. The effects of erythromycin suggest that absorption of fexofenadine involves an uptake transport in addition to passive diffusion in the jejunum and predominantly passive diffusion in the ileum and colon.

Once-daily immediate-release fexofenadine and sustained-release pseudoephedrine combination: a new treatment option for allergic rhinitis

Allergic rhinitis symptoms, in particular nasal congestion, can have a significant impact on patient quality of life, resulting in reduced productivity and daytime sleepiness. Newer-generation antihistamines are commonly used to treat allergic rhinitis; however, in patients with severe congestion, a combination of a newer-generation antihistamine and a decongestant is particularly beneficial. A new once-daily fexofenadine/pseudoephedrine combination has been developed and recently approved in the US. The combination provides an effective, well-tolerated antihistamine and a reliable, sustained-release pseudoephedrine system. In addition, small tablet size and once-daily dosing may provide patients with increased convenience and improve adherence. In summary, the combination of immediate-release fexofenadine/sustained-release pseudoephedrine offers an important additional option for the treatment of allergic rhinitis.

Effect of pretreatment with fexofenadine on the safety of immunotherapy in patients with allergic rhinitis

BACKGROUND

Allergen-specific immunotherapy, although not a cure, remains the only treatment available that can alter the natural course of an allergic disease. However, the risk of allergen specific immunotherapy-related systemic reactions (SRs), reported to occur in approximately 1% to 14% of patients and which can range from mild to fatal in seriousness, represents a barrier to implementing this unique and effective treatment option.

OBJECTIVE

To explore the possibility that pretreatment with the H1-antihistamine fexofenadine could prevent the occurrence of severe SRs induced by immunotherapy in Japanese patients with allergic rhinitis.

METHODS

In this open-label, multicenter study, 134 patients receiving immunotherapy for allergic rhinitis were randomized 1:1 to a group receiving pretreatment with fexofenadine hydrochloride (60 mg) 2 hours before immunization injection (n = 67) or to a control group receiving no pretreatment (n = 67). Patients were further grouped into those who received cedar pollen immunotherapy and those who received dust mite immunotherapy.

RESULTS

Pretreatment with fexofenadine 2 hours before immunotherapy significantly reduced the occurrence of severe SRs (P = .03), significantly increased the proportion of patients receiving cedar pollen immunotherapy who achieved the target maintenance dose (TMD) (P = .03), and significantly reduced the length of time to attain the TMD (P = .047 and P = .003 for patients receiving cedar pollen and dust mite immunotherapy, respectively).

CONCLUSIONS

This study suggests a novel role for fexofenadine in enhancing the safety of immunotherapy and increasing the proportion of patients achieving the TMD.

Efficacy of fexofenadine in the prophylactic control of cat allergen-induced allergic rhinitis

BACKGROUND

To date, it is unknown whether fexofenadine mitigates the worsening of symptoms induced by the cat allergen Felis domesticus allergen 1.

OBJECTIVE

To determine the effects of a single dose of fexofenadine hydrochloride, 180 mg, in preventing and controlling cat allergen-induced allergic rhinitis symptoms using the cat room challenge model.

METHODS

This single-center, randomized, double-blind, placebo-controlled, 2-way crossover study consisted of a screening visit, 1 or 2 qualifying visits, and 2 treatment periods separated by a mean +/- SD washout period of 14 +/- 3 days. Patients were randomized to treatment sequence 1 (placebo followed by fexofenadine) or sequence 2 (fexofenadine followed by placebo). Baseline end points were obtained before study drug administration, and allergen challenges were initiated 1 1/2 hours after dosing. The primary end point was the change from predose baseline in the total symptom score (sum of rhinorrhea, itchy nose/palate/ throat, sneezing, and itchy/watery/red eyes) after 30 minutes of allergen exposure compared with placebo.

RESULTS

Of 211 patients screened, 66 were randomized and 63 completed the study. Mean change in the total symptom score from predose baseline was significantly less with fexofenadine compared with placebo 30 minutes after initiation of the cat allergen challenge (2 hours after dosing) (P = .03). The overall incidence of treatment-emergent adverse events was low and comparable for both groups.

CONCLUSION

Prophylactic treatment with a single dose of fexofenadine hydrochloride, 180 mg, significantly mitigated the worsening of allergic rhinitis symptoms induced by exposure to cat allergen compared with placebo use.

In Vivo Pharmacological Characterisation of Bilastine, a Potent??and Selective Histamine H1??Receptor Antagonist

OBJECTIVE

We set out to establish the in vivo histamine H(1) receptor antagonistic (antihistaminic) and antiallergic properties of bilastine.

METHODS

In vivo antihistaminic activity experiments consisted of measurement of: inhibition of increase in capillary permeability and reduction in microvascular extravasation and bronchospasm in rats and guinea pigs induced by histamine and other inflammatory mediators; and protection against lethality induced by histamine and other inflammatory mediators in rats. In vivo antiallergic activity experiments consisted of measurement of passive and active cutaneous anaphylactic reactions as well as type III and type IV allergic reactions in sensitised rodents.

RESULTS

In the in vivo antihistaminic activity experiments, bilastine was shown to have a positive effect, similar to that of cetirizine and more potent than that of fexofenadine. The results of the in vivo antiallergic activity experiments showed that the properties of bilastine in this setting are similar to those observed for cetirizine and superior to fexofenadine in the model of passive cutaneous anaphylactic reaction. When active cutaneous anaphylactic reaction experiments were conducted, bilastine showed significant activity, less potent than that observed with cetirizine but superior to that of fexofenadine. Evaluation of the type III allergic reaction showed that of the antihistamines only bilastine was able to inhibit oedema in sensitised mice, although its effect in this respect was much less potent than that observed with dexamethasone. In terms of the type IV allergic reaction, neither bilastine, cetirizine nor fexofenadine significantly modified the effect caused by oxazolone.

CONCLUSIONS

The results of our in vivo preclinical studies corroborate those obtained from previously conducted in vitro experiments of bilastine, and provide evidence that bilastine possesses antihistaminic as well as antiallergic properties, with similar potency to cetirizine and superior potency to fexofenadine.

The efficacy and safety of 30 mg fexofenadine HCl bid in pediatric patients with allergic rhinitis

Allergic rhinitis is one of the most common chronic disorders in children. It is also one of the most common causes of absence from school. This study reports on the efficacy and safety of a twice-daily oral dose of fexofenadine HCl 30 mg in Asian children aged 6-11 years diagnosed with seasonal or perennial allergic rhinitis. A total of 100 children with a history of allergic rhinitis for more than one year and a positive prick skin test response to at least one of the common aeroallergens in Thailand were enrolled in this multi-center, open-label, non comparative study. The severity of individual symptoms such as sneezing, rhinitis, etc. and adverse events were recorded in diary cards by the patients in form of scores as well as by the investigator at each visit. The total symptom score (TSS) with or without blocked nose at baseline, week 1 and week 2 was recorded. The TSS was defined as the sum of the individual symptom scores except for the nasal blockage score, as nasal blockage was not expected to respond to antihistamine treatment. Only patients with a total symptom score > or = 6 were included in the study. There was a statistically significant improvement at p < 0.01 for the TSS with or without blocked nose and for each symptom score such as blocked nose, sneezing, rhinorrhea, itchy nose/palate and/or throat, and itchy/watery/red eyes from baseline to week 1 and week 2. Additionally, there was a statistically significant improvement between week 1 and week 2 for itchy nose/palate and/or throat and itchy/watery/red eyes (p < 0.05). The Kappa measure of agreement was statistically significant at p < 0.001 between investigator's and patient's/parent's assessment, indicating the same degree of satisfaction with the overall effectiveness of the treatment. Fexofenadine 30 mg bid is effective in reducing the total symptom score of allergic rhinitis including blocked nose and is generally well tolerated. It is not cardiotoxic and is safe for pediatric patients as young as 6 years of age.

[Wheat anaphylaxis enhanced by administration of acetylsalicylic acid or by exercise]

A 23-year-old woman experienced generalized urticaria and loss of consciousness during walking after ingestion of wheat. Skin prick test and CAP-RAST were positive for gluten. An oral challenge test using 100g wheat was positive without exercise. The patient was given diagnosis of wheat allergy. In addition, not only exercise but also administration of 500mg aspirin were found to exacerbate her symptoms after the ingestion of wheat, suggesting that acetylsalicylic acid could be an augmentation factor in wheat allergy. Etodorac failed to enhance the symptoms. Further, oral administration of Fexofenadine could prevent allergic reactions induced by ingestion of 100g wheat, but sodium cromoglycate partially reduced the reactions.

Levocetirizine has a longer duration of action on improving total nasal symptoms score than fexofenadine after single administration

AIMS

To compare the onset and duration of action of the new antihistamine levocetirizine with that of the second-generation antihistamine fexofenadine using the Vienna Challenge Chamber (VCC). The latter is an environment where subjects can be exposed to specific aeroallergens in controlled and reproducible conditions allowing for precise comparisons of anti-allergic drugs.

METHODS

Ninety-four subjects received a single dose of levocetirizine 5 mg, fexofenadine 120 mg or placebo in a random order using a three-way cross-over design. On day 1, subjects were exposed to grass pollens (1500 grains/m(3)) in the VCC over a period of 4 h. Treatment was given 2 h after the start of challenge. On day 2, 22 h after drug intake, subjects were again exposed to pollens for 6 h. Specified symptoms were assessed by the subjects every 15 min using 5-point scales. The main efficacy parameter was the change from baseline in the Major Symptom Complex Score (MSCS = sum of rhinorrhea, sneezing, itchy nose and eyes).

RESULTS

Baseline characteristics, including symptoms scores, were similar in the three study groups. During the first 2 h after drug intake both antihistamines achieved clinically relevant and significant (P < 0.001) improvements in symptom scores. Twenty-two to 24 h after drug intake, mean (SEM) MSCS reductions were: 1.9 (0.3) after placebo (baseline of 9.7), 3.8 (0.3) after fexofenadine (baseline of 9.9), and 5.1 (0.3) after levocetirizine (baseline of 9.8). Levocetirizine was significantly (P < 0.001) more effective than fexofenadine with a score difference of 1.3 (95% CI 0.7, 1.9). This was maintained until the end of the study (up to 28 h).

CONCLUSIONS

A rapid onset of action in alleviating seasonal allergic rhinitis (SAR) symptoms of subjects exposed to grass pollens in the VCC was observed after levocetirizine and fexofenadine. Levocetirizine was more effective than fexofenadine at and later than 22 h after drug intake, an indication of the longer-duration of action of levocetirizine.

Effect of itraconazole on the pharmacokinetics and pharmacodynamics of fexofenadine in relation to the MDR1 genetic polymorphism

OBJECTIVE

Our objective was to evaluate the effect of itraconazole, a P-glycoprotein inhibitor, on the pharmacokinetics and pharmacodynamics of fexofenadine, a P-glycoprotein substrate, in relation to the multidrug resistance 1 gene (MDR1) G2677T/C3435T haplotype.

METHODS

A single oral dose of 180 mg fexofenadine was administered to 7 healthy subjects with the 2677GG/3435CC (G/C) haplotype and 7 with the 2677TT/3435TT (T/T) haplotype. One hour before the fexofenadine dose, either 200 mg itraconazole or placebo was administered to the subjects in a double-blinded, randomized, crossover manner with a 2-week washout period. Histamine-induced wheal and flare reactions were measured to assess the effects on the antihistamine response.

RESULTS

In the placebo phase, pharmacokinetic parameters of fexofenadine showed no statistically significant difference between 2 MDR1 haplotypes; the area under the curve from time 0 to infinity (AUC(0-infinity)) of fexofenadine in the T/T and G/C groups was 5194.0 +/- 1910.8 and 4040.4 +/- 1832.2 ng.mL(-1).h(-1), respectively (P = .271), and the oral clearance (CL/F) was 530.9 +/- 191.1 and 806.0 +/- 355.3 mL.h(-1).kg(-1), respectively (P = .096). The disposition of itraconazole, a substrate of P-glycoprotein, was not significantly different between the 2 haplotypes. After itraconazole pretreatment, however, the differences in fexofenadine pharmacokinetics became statistically significant; the mean fexofenadine AUC(0-infinity) in the T/T group was significantly higher than that in the G/C group (15,630.6 +/- 5070.0 and 9252.9 +/- 2044.1 ng/mL.h, respectively; P = .007), and CL/F of the T/T subjects was lower than that of the G/C subjects (167.0 +/- 33.3 and 292.3 +/- 42.2 mL.h(-1).kg(-1), respectively; P < .001). Itraconazole pretreatment caused more than a 3-fold increase in the peak concentration of fexofenadine and the area under the curve to 6 hours compared with the placebo phase. This resulted in a significantly higher suppression of the histamine-induced wheal and flare reactions in the itraconazole pretreatment phase compared with those in the placebo phase.

CONCLUSION

The effect of MDR1 G2677T/C3435T haplotypes on fexofenadine disposition are magnified in the presence of itraconazole. Itraconazole pretreatment significantly altered the disposition of fexofenadine and thus its peripheral antihistamine effects.

Suppression of the histamine-induced wheal and flare response by fexofenadine HCl 60 mg twice daily, loratadine 10 mg once daily and placebo in healthy Japanese volunteers

BACKGROUND

The effects of the selective H1-receptor antagonist fexofenadine have been widely demonstrated in Western populations; however, to date, limited data comparing the effects of fexofenadine with other antihistamines have been reported in Japanese subjects.

OBJECTIVE

To investigate the effect of fexofenadine and loratadine on the histamine-induced cutaneous wheal and flare response in healthy Japanese volunteers.

METHODS

Eighteen healthy male and female Japanese volunteers aged 20-53 years were randomized to receive fexofenadine HCl 60 mg twice daily, loratadine 10 mg once daily or placebo in a 1-day, three-period, double-blind, crossover study. For each treatment, the wheal and flare response to 100 mg/mL histamine was assessed at baseline and at 1, 1.5, 2, 2.5, 3, 3.5, 4, 8, 12 and 24 hours post-dose. Blood samples were taken for pharmacokinetic analysis.

RESULTS

Fexofenadine produced significantly greater percentage suppression of the overall wheal response compared with placebo and loratadine (43.1% versus 10.0% and 15.2%, respectively; p < 0.001). Similarly, fexofenadine significantly suppressed the overall flare response compared with placebo and loratadine (43.0% versus 3.5% and -8.9%, respectively; p < 0.01). Loratadine was statistically no different from placebo in terms of both overall wheal and flare suppression. Area under the curve analysis for wheal and flare reduction (0-12 hours post-dose) confirmed these findings. For wheal inhibition, fexofenadine had a significantly faster onset of action (defined as time to > or = 35% inhibition) compared with placebo (p < 0.001) and loratadine (p < 0.01); for flare, fexofenadine had a significantly faster onset of action than loratadine (p < 0.01). Mean maximum inhibition (the mean of the greatest inhibition achieved from baseline for each treatment) for wheal was achieved significantly faster with fexofenadine than loratadine (p < 0.01), and fexofenadine had a significantly longer duration of effect on suppressing wheal and flare compared with placebo and loratadine (p < 0.05 for all). The antihistamine effects of fexofenadine correlated significantly with its Cmax, while loratadine activity did not correlate significantly with its plasma levels.

CONCLUSIONS

Fexofenadine is a potent suppressor of the histamine-induced wheal and flare response in healthy Japanese volunteers. These results support findings in Caucasian subjects, and confirm that fexofenadine has greater antihistaminergic activity than loratadine in this human model.

Once-daily fexofenadine treatment for chronic idiopathic urticaria: a multicenter, randomized, double-blind, placebo-controlled study

BACKGROUND

Chronic idiopathic urticaria (CIU) can have a profound effect on patients' health and quality of life.

OBJECTIVE

To evaluate the efficacy and safety of once-daily dosing of fexofenadine hydrochloride, 180 mg, on CIU.

METHODS

This randomized, double-blind, parallel-group, placebo-controlled study consisted of a placebo run-in period followed by a 4-week treatment period. Patients 12 years and older with active CIU were randomized 2:1 to receive once-daily fexofenadine, 180 mg, or placebo. The primary end points were change from baseline in mean daily number of wheals (MNW score) and mean daily severity of pruritus during treatment. Secondary efficacy measures included modified total symptom scores and MNW and pruritus severity scores evaluated weekly and instantaneously at trough drug levels.

RESULTS

Patients administered fexofenadine (n = 163) experienced significantly greater improvements in MNW and pruritus severity scores compared with the placebo group (n = 92) (P < .001 for both). Similarly, throughout treatment and at each individual week, the mean reductions in modified total symptom scores were significantly greater in the fexofenadine group (P < or = .005 for all comparisons vs placebo). The mean reductions in instantaneous MNW and pruritus severity scores were greater in patients in the fexofenadine group than in those who received placebo (MNW score: P = .015; pruritus severity score: P < .001). There were no significant differences in the frequency of treatment-emergent adverse events between the 2 treatment groups.

CONCLUSIONS

A once-daily dose of fexofenadine hydrochloride, 180 mg, offered effective, well-tolerated relief for the management of CIU.