Second-Generation Antihistamines

Greens appraisal of validated stability indicating RP-HPLC method and forced degradation study for quantification of Ebastine in wastewater and dosage form

OBJECTIVES

Allergic rhinitis and chronic idiopathic urticaria are common conditions triggered by environmental irritants, stress, and certain foods. The FDA has recently announced that the efficacy and safety of Ebastine (EBS) have been thoroughly evaluated and confirmed. This study considered using various tools to assess their greenness. We used AGREEprep, analytical eco-scale (ESA), and analytical method volume intensity (AMVI) to evaluate the greenness of the validated stability-indicating method and a forced degradation study. This allowed for easy determination and quantitation of EBS in wastewater and dosage form.

METHODS

The method was established on Symmetry RP-C18 (150mm×4.6mm,5μm) using mobile phase, which can be prepared by mixing buffer solution of pH 3 with acetonitrile in a ratio of (37.5: 62.5, v/v) in addition to dissolving 0.72 gm of sodium lauryl sulfate in the final solution. The separation process was executed at a flow rate of 1.5mL/min and 5μL injection volume with UV detection at 254nm. Linearity was conducted for EBS in the 5-50μg/mL range. Different validation parameters were investigated, including accuracy, precision, robustness, and specificity.

RESULTS

The limits of both detection and quantification were 0.84μg/mL and 2.57μg/mL for EBS. The recovery percentages of EBS were found to be 101.01% and 101.02% for wastewater and pharmaceutical formulations, respectively.

CONCLUSION

According to International Council for Harmonisation (ICH) guidelines, a forced degradation study of EBS was evaluated, including acid, base hydrolysis, and oxidative hydrolysis using hydrogen peroxide and photolytic and thermal degradation. The highest degradation was achieved by acid hydrolysis. The safety and efficacy of EBS were evaluated via a safety comparative profile study.

Flight safety risk assessment of self-medication among fighter pilots: a cross-sectional study

BACKGROUND

Fighter pilots are a specific population in which any adverse drug reaction can unpredictably interact with aeronautical constraints and thus compromise flight safety. This issue has not been evaluated in risk assessments.

AIM

To provide a semi-quantitative assessment of the risk to flight safety of self-medication in fighter pilots.

METHOD

A cross-sectional survey that aimed at identifying the determinants of self-medication in fighter pilots was conducted. All medications consumed within 8 h preceding a flight were listed. A modified Failure Mode and Effects Analysis was performed, and any adverse drug reaction reported in the French marketing authorization document of a drug was considered a failure mode. The frequency of occurrence and severity were evaluated using specific scales to assign each to three risk criticality categories: acceptable, tolerable, and unacceptable.

RESULTS

Between March and November 2020, the responses of 170 fighter pilots were analyzed, for an overall return rate of approximately 34%. Among them, 78 reported 140 self-medication events within 8 h preceding a flight. Thirty-nine drug trade names (48 different international nonproprietary names) were listed, from which 694 potential adverse drug reactions were identified. The risk criticality was considered unacceptable, tolerable and acceptable for 37, 325 and 332 adverse drug reactions, respectively. Thus, the risk criticality was considered unacceptable, tolerable and acceptable for 17, 17, and 5 drugs, respectively.

CONCLUSION

This analysis suggests that the overall risk to flight safety of the current practice of self-medication in fighter pilots may be considered at least tolerable, or even unacceptable.

Managing anaphylaxis: Epinephrine, antihistamines, and corticosteroids: More than 10 years of Cross-Canada Anaphylaxis REgistry data

BACKGROUND

Epinephrine is the first-line treatment for anaphylaxis but is often replaced with antihistamines or corticosteroids. Delayed epinephrine administration is a risk factor for fatal anaphylaxis. Convincing data on the role of antihistamines and corticosteroids in anaphylaxis management are sparse.

OBJECTIVE

To establish the impact of prehospital treatment with epinephrine, antihistamines, and/or corticosteroids on anaphylaxis management.

METHODS

Patients presenting with anaphylaxis were recruited prospectively and retrospectively in 10 Canadian and 1 Israeli emergency departments (EDs) between April 2011 and August 2022, as part of the Cross-Canada Anaphylaxis REgistry. Data on anaphylaxis cases were collected using a standardized form. Primary outcomes were uncontrolled reactions (>2 doses of epinephrine in ED), no prehospital epinephrine use, use of intravenous fluids in ED, and hospital admission. Multivariate regression was used to identify factors associated with primary outcomes.

RESULTS

Among 5364 reactions recorded, median age was 8.8 years (IQR, 3.78-16.9); 54.9% of the patients were males, and 52.5% had a known food allergy. In the prehospital setting, 37.9% received epinephrine; 44.3% received antihistamines, and 3.15% received corticosteroids. Uncontrolled reactions happened in 250 reactions. Patients treated with prehospital epinephrine were less likely to have uncontrolled reactions (adjusted odds ratio [aOR], 0.955 [95% CI, 0.943-0.967]), receive intravenous fluids in ED (aOR, 0.976 [95% CI, 0.959-0.992]), and to be admitted after the reaction (aOR, 0.964 [95% CI, 0.949-0.980]). Patients treated with prehospital antihistamines were less likely to have uncontrolled reactions (aOR, 0.978 [95% CI, 0.967-0.989]) and to be admitted after the reaction (aOR, 0.963 [95% CI, 0.949-0.977]). Patients who received prehospital corticosteroids were more likely to require intravenous fluids in ED (aOR, 1.059 [95% CI, 1.013-1.107]) and be admitted (aOR, 1.232 [95% CI, 1.181-1.286]).

CONCLUSION

Our findings in this predominantly pediatric population support the early use of epinephrine and suggest a beneficial effect of antihistamines. Corticosteroid use in anaphylaxis should be revisited.

Pollen respiratory allergy: Is it really seasonal?

Allergic rhinitis (AR) is a highly prevalent respiratory condition that carries a heavy burden and can have a significant impact on patient quality of life. AR is caused by seasonal or perennial exposure to outdoor pollens and molds as well as indoor allergic triggers. In this review article, we discuss the factors associated with the development of AR throughout the year and the fact that patients with AR need continuous treatment rather than seasonal treatment. Conventionally, AR has been mainly categorized into seasonal AR and perennial AR, but these classes do not seem to be well-adapted. Climate changes, temperature changes, and high carbon dioxide (CO₂) concentration affect the growth of plants and increase the length of pollen seasons and pollen allergenicity. Air pollution aggravates allergic sensitization symptoms in AR sensitized individuals. Due to increased air pollution and indefinite pollen seasons AR symptoms are present throughout the year. Patients with AR often need continuous treatment, which should be considered while making the strategy for treating allergic rhinitis sufferers. Management of AR involves avoiding the allergen, medications for symptomatic relief, anti-inflammatory therapies, and allergy immunotherapy. Although the first-generation H₁-antihistamines reduce AR symptoms, they cause sedation and impair cognitive functions; thus, second-generation antihistamines (ie, levocetirizine, loratadine, bilastine, fexofenadine) are preferred. The efficacy and safety of fexofenadine for the treatment of seasonal allergic rhinitis (SAR) symptoms have been demonstrated by numerous clinical studies, irrespective of the season and underlying allergen. In this review, we discuss the allergic rhinitis classification, the role of climate change, air pollution, and factors contributing to year-round symptoms in patients with AR and the need for continuous pharmacological treatment for management.

Updates in the diagnosis and practical management of allergic rhinitis

INTRODUCTION

Allergic rhinitis (AR) is a widespread disease that can be associated with other conditions, including conjunctivitis, rhinosinusitis, asthma, food allergy, and atopic dermatitis. Diagnosis is based on the history and documentation of sensitization, such as the production of allergen-specific IgE, preferably using molecular diagnostics. Treatments are based on patient education, non-pharmacological and pharmacological remedies, allergen-specific immunotherapy (AIT), and surgery. Symptomatic treatments mainly concern intranasal/oral antihistamines and/or nasal corticosteroids.

AREAS COVERED

This review discusses current and emerging management strategies for AR, covering pharmacological and non-pharmacological remedies, AIT, and biologics in selected cases with associated severe asthma. However, AIT presently remains the unique causal treatment for AR.

EXPERT OPINION

The management of allergic rhinitis could include new strategies. In this regard, particular interest should be considered in the fixed association between intranasal antihistamines and corticosteroids, probiotics and other natural substances, and new formulations (tablets) of AIT.

Allergic Rhinitis in Children and Adolescents

Allergic rhinitis is a common disorder that regularly occurs in children and adolescents. The disease is associated with other allergic diseases, such as asthma, and it carries a heavy burden, with effects on sleep, school performance, and quality of life. Classic symptoms include sneezing, rhinorrhea, nasal obstruction, and nasal itching. When the eyes are involved, the term allergic rhinoconjunctivitis is used. Triggers may include airborne pollens, molds, dust mites, and animals. Skin or blood allergy testing can be a useful diagnostic modality that may guide therapy. Immunotherapy can prevent the development of further allergic sensitizations as well as subsequent asthma.

Applying Biopharmaceutical Classification System criteria to predict the potential effect of Cremophor® RH 40 on fexofenadine bioavailability at higher doses

Aim: To study the impact of various permeability enhancers on fexofenadine bioavailability. Furthermore, to predict the potential effect of Cremophor^® RH 40 on fexofenadine pharmacokinetics at higher doses using Biopharmaceutical Classification System criteria. Experimental methods: The effect of the dose increase (60-360 mg) on the dissolution and permeability behavior of fexofenadine-Cremophor RH 40 formulations was studied in humans. The Biopharmaceutical Classification System criteria of the drug was determined. Results & conclusion: Cremophor RH 40 improved the dissolution and bioavailability of fexofenadine. The pharmacokinetics increased linearly with the dose increase. Absorption number (A_n) was significantly increased after addition of Cremophor RH 40 in comparison to an unprocessed drug. Similar A_n values were observed throughout the same dose range. The dose number (D₀) values were <1 whereas, all the dissolution number (D_n) values were >1 at the same dose level.

Allergic Rhinitis in Children and Adolescents

Allergic rhinitis is a common disorder that regularly occurs in children and adolescents. The disease is associated with other allergic diseases, such as asthma, and it carries a heavy burden, with effects on sleep, school performance, and quality of life. Classic symptoms include sneezing, rhinorrhea, nasal obstruction, and nasal itching. When the eyes are involved, the term allergic rhinoconjunctivitis is used. Triggers may include airborne pollens, molds, dust mites, and animals. Skin or blood allergy testing can be a useful diagnostic modality that may guide therapy. Immunotherapy can prevent the development of further allergic sensitizations as well as subsequent asthma.

Comparative Study of Chemical Stability of Two H1 Antihistaminic Drugs, Terfenadine and Its In Vivo Metabolite Fexofenadine, Using LC-UV Methods

A comparative study of chemical stability of terfenadine (TER) and its in vivo metabolite fexofenadine (FEX) was performed. Both TER and FEX were subjected to high temperature at different pH and UV/VIS light at different pH and then quantitatively analyzed using new validated LC-UV methods. These methods were used to monitor the degradation processes and to determine the kinetics of degradation for both the compounds. As far as the effects of temperature and pH were concerned, FEX occurred more sensitive to degradation than TER. As far as the effects of UV/VIS light and pH were concerned, the both drugs were similarly sensitive to high doses of light. Using all stress conditions, the processes of degradation of TER and FEX followed the first-order kinetics. The results obtained for these two antihistaminic drugs could be helpful in developing their new derivatives with higher activity and stability at the same time.

Antipruritic Placebo Effects by Conditioning H1-antihistamine

OBJECTIVE

Allergic rhinitis symptoms can be reduced by behaviorally conditioning antihistamine. It is unclear whether these findings extend to histamine-induced itch or work when participants are informed about the conditioning procedure (open-label conditioning). The current study aims to investigate the efficacy of (open-label) antipruritic behavioral conditioning for histamine-induced itch.

METHODS

Healthy participants (n = 92; 84% female) were randomized to I) an open-label conditioned, II) closed-label conditioned, III) conditioned-not-evoked control, or IV) nonconditioned control group. A two-phase conditioning paradigm was used. During acquisition, a conditioned stimulus (CS; distinctively tasting beverage) was repeatedly paired with the H1-antihistamine levocetirizine (groups I-III). During evocation, the CS was paired with placebo (I, II), or instead of the CS, water was paired with placebo (III). The nonconditioned control group (IV) received CS with placebo in both phases. Itch after histamine iontophoresis and physiological data (i.e., spirometry, heart rate, skin conductance) were assessed. Combined conditioned and combined control groups were first compared, and analyses were repeated for separate groups.

RESULTS

Marginally lower itch was reported in the combined conditioned compared with the control groups (F(1,88) = 2.10, p = .076, ηpartial = 0.02); no differences between separate groups were found. No effects on physiological data were found, except for heart rate, which reduced significantly and consistently for control groups, and less consistently for conditioned groups (group by time interaction: F(7,80) = 2.35, p = .031, ηpartial = 0.17).

CONCLUSION

Limited support was found for the efficacy of antipruritic behavioral conditioning, regardless of whether participants were informed about the conditioning procedure. The application of open-label conditioning in patient populations should be further researched.

TRIAL REGISTRATION

www.trialregister.nl; ID NTR5544.

Polypharmacy leads to increased prevalence of potentially inappropriate medication in the Indonesian geriatric population visiting primary care facilities

Background

The geriatric population is particularly vulnerable to being prescribed potentially inappropriate medication (PIM); however, the prevalence of this occurrence remains poorly investigated in Indonesia. Thus in this research, we focused on investigating the prevalence and predictors of PIM among the Indonesian geriatric population in a primary health care setting.

Methods

A retrospective observational study was conducted in 25 primary health care facilities in Karawang District, Indonesia. The medical prescriptions of patients aged ≥60 years during January–December 2014 were documented, and the PIM was assessed based on Beers and McLeod criteria. The influence of age, sex, number of diseases, and polypharmacy toward PIM was assessed using a logistic regression model. A P-value of <0.05 defined statistical significance.

Results

A total of 3,819 subjects were included in the study. PIM was highly prevalent (52.2%) among the Indonesian elderly. Chlorpheniramine, mefenamic acid, ibuprofen, and nifedipine were the most commonly prescribed PIM. Polypharmacy (odds ratio: 1.2 [0.6, 2.1]) was the only factor associated with the use of PIM, while sex, age, and multiple diseases did not show significant association.

Conclusion

PIM is a concern in the Indonesian geriatric population. Health care professionals are encouraged to review the medications of their geriatric patients using updated safety guidelines to prevent risks associated with PIM.

Combining MucilAir™ and Vitrocell® Powder Chamber for the In Vitro Evaluation of Nasal Ointments in the Context of Aerosolized Pollen

Hay fever is notoriously triggered when nasal mucosa is exposed to allergenic pollen. One possibility to overcome this pollen exposure may be the application of an ointment with physical protective effects. In this context, we have investigated Bepanthen^® Eye and Nose Ointment and the ointment basis petrolatum as reference while using contemporary in vitro techniques. Pollen from false ragweed (Iva xanthiifolia) was used as an allergy-causing model deposited as aerosol using the Vitrocell^® Powder Chamber (VPC) on Transwell^® inserts, while being coated with either Bepanthen^® Eye and Nose Ointment and petrolatum. No pollen penetration into ointments was observed upon confocal scanning laser microscopy during an incubation period of 2 h at 37 °C. The cellular response was further investigated by integrating the MucilAir™ cell system in the VPC and by applying pollen to Bepanthen^® Eye and Nose Ointment covered cell cultures. For comparison, MucilAir™ were stimulated by lipopolysaccharides (LPS). No increased cytokine release of IL-6, TNF-α, or IL-8 was found after 4 h of pollen exposure, which demonstrates the safety of such ointments. Since nasal ointments act as a physical barrier against pollen, such preparations might support the prevention and management of hay fever.

Effects of inclusion of cetirizine hydrochloride in β-cyclodextrin

Following the preparation of inclusion complex of cetirizine (CTZ) and β-cyclodextrin (β-CD), the compound was investigated to assess the possibility of modifying the physicochemical properties (solubility, release, stability, permeability) of CTZ after complexation that are vital for subsequent formulation studies involving the said complex. Changes in FT-IR/Raman spectra, DSC thermograms and XRD diffractograms confirmed the formation of a CTZ-β-CD system. Hydrophilic interaction chromatography with a DAD detector was employed to determine alterations of the CTZ concentration during studies following complexation. An analysis of a phase-solubility diagram of c_CTZ = fc_β-CD indicated a linear rise in the solubility of CTZ as the concentration of β-CD increased. The inclusion of CTZ in a system with β-CD significantly reduced the instability of CTZ in the presence of oxidizing factors. It was also found that regardless of the pH of the acceptor fluids used in the release studies an increase was observed in the concentration of CTZ in CD system compared to its free form. The ability to permeate artificial biological membranes manifested by CTZ after complexation was enhanced as well. In summary, CD has significant potential to mask the bitter taste of CTZ and to counter the instability induced by oxidizing factors.

Efficacy and safety of using a warming needle for persistent allergic rhinitis: study protocol for a randomized controlled trial

Background

Many previous studies have shown the potential therapeutic effect of acupuncture for allergic rhinitis. Most of these studies, however, were limited by the short duration of observations and lack of sham acupuncture as the control group. Our preliminary experiments showed that the use of a warm needling achieved a much more persistent effect in the treatment of allergic rhinitis (AR) compared with simple acupuncture therapy. Hence, we have designed a multicenter, randomized controlled trial (RCT) in which the first-line medication loratadine will be used as the control group, and the effect of warm needling therapy will be evaluated through long-term observation.

Methods/design

The trial is designed as a multicenter, parallel-group, randomized, single-blinded (outcome assessors), non-inferiority trial. A total of 98 patients with persistent AR will be randomly assigned into two groups. Patients in the treatment group will be treated with warm needling at GV14 and acupuncture at EX-HN3, ST2, LI20, EX-HN8, GV23, LU7, LU5 and LI4 three times a week, for a total of 4 weeks. Patients in the control group will be treated with oral loratadine 10 mg/day for 4 weeks. The primary outcome will be the change in the Total Nasal Symptom Score (TNSS) from baseline to that at 6 months after treatment during the follow-up period. The secondary outcomes will include the Total Non-nasal Symptom Score and the Rhinoconjunctivitis Quality of Life Questionnaire, changes in the TNSS from baseline to that at 2 and 4 weeks during treatment, and 3 months after treatment during the follow-up period. Outcomes will be measured at 2 and 4 weeks, and 3 and 6 months after treatment. Any side effects of treatment will be observed and recorded.

Discussion

We expect that the study results will provide evidence to determine the effects of warm needling compared with loratadine. Our final goal of the study is to evaluate the difference in the short-term and long-term effects between the two therapeutic methods, especially the long-term effect of warm needling.

Trial registration

ClinicalTrials.gov NCT02339714. Registered on 14 January 2015.

Electronic supplementary material

The online version of this article (doi:10.1186/s13063-016-1432-z) contains supplementary material, which is available to authorized users.

Concomitant drugs with low risks of drug-drug interactions for use in oncology clinical trials

BACKGROUND

Drug-drug interactions (DDIs) may occur with investigational drugs and affect patient safety, trial outcomes, and drug development. A list of preferred drugs with minimal risks of DDIs for treatment of symptoms or comorbidities frequently encountered by cancer patients would be helpful.

METHODS

We reviewed the literature to assess DDIs reported for the main drugs available for treatment of symptoms/comorbidities frequently encountered by cancer patients. Reviews and relevant original articles cited were retrieved and analyzed, and the following data were collected and double-checked: pharmacological properties; effects, if any, of drugs on CYP enzymes, membrane transporters, and QT interval; and involvement in significant DDIs.

RESULTS

A list of preferred drugs with minimal risks of DDIs was compiled.

CONCLUSION

Acknowledging for heterogeneity in data sources, prevention of unexpected DDIs during clinical trials may be improved by using this list of preferred drugs for the management of study patient's symptoms.

Respiratory allergies: a general overview of remedies, delivery systems, and the need to progress

The spread of respiratory allergies is increasing in parallel with the alarm of the scientific community. Evidently, our knowledge of the onset mechanisms of these diseases and, as a consequence, of the available remedies is inadequate. This review provides a brief, general description of current therapeutic resources and the state of research with regard to both drugs and medical devices in order to highlight their limits and the urgent need for progress. Increasing the amount of basic biochemical research will improve our knowledge of such onset mechanisms and the potential efficacy of therapeutic preparations.

The clinical use of cetirizine in the treatment of allergic rhinitis

BACKGROUND

Cetirizine is among the first second-generation H1 antihistamines (SGAHs) developed to provide selective H1 receptor inhibition without central nervous system depression.

OBJECTIVE

The aim of this review is to summarize the amount of data collected over 25 years of clinical use of cetirizine and compare this with data available for other SGAHs in the management of patients with allergic rhinitis (AR).

METHODS

A comprehensive literature search for publications relating to cetirizine was performed using the Pubmed database, and relevant papers published in English were selected for detailed review.

RESULTS

Compared with the majority of other SGAHs, cetirizine was generally shown to have a more favourable pharmacological profile, to be well tolerated, be at least equally or more efficacious in attenuating/inhibiting nasal and ocular symptoms and to improve the quality of life in AR patients. The majority of clinical trials investigating the effect of SGAHs in AR patients further indicated that cetirizine was often employed as the main comparator active drug.

CONCLUSION

Based on the evidence that cetirizine is a commonly employed active comparator drug in AR, it is tempting to suggest that cetirizine may be a suitable benchmark in the development of novel pharmacotherapies for AR.

Variability of histamine pharmacodynamic response in children with allergic rhinitis

Histamine iontophoresis with laser Doppler monitoring (HILD) is a robust and dynamic surrogate for histamine microvasculature response. We characterized histamine pharmacodynamics in children using HILD. HILD was performed in 54 children with allergic rhinitis. A non-compartmental analysis and non-linear mixed-effects model with a linked effect PK/PD model was used to provide estimates for area under the effect curve (AUEC), maximal response over baseline (EffmaxNT), and time of EffmaxNT (Tmax). Data were placed in sub-groups by visualization of time vs. response relationships. ANOVA and regression analyses were used for sub-group comparisons. Three histamine response phenotypes were identified. One group demonstrated a hyper-responsive phenotype (higher Tmax, EffmaxNt and AUEC, P < .01). AUEC and EffmaxNT were more strongly associated in this group (r(2)  = 0.86) than the entire cohort (r(2)  = 0.64). These data demonstrate a hyper-responsive histamine phenotype via HILD. This finding is important to future pharmacologic studies of antihistamines.

Antihistamine therapy in allergic rhinitis

Antihistamines have long been a mainstay in the therapy for allergic rhinitis. Many different oral antihistamines are available for use, and they are classified as first generation or second generation based on their pharmacologic properties and side-effect profiles. The recent introduction of intranasal antihistamines has further expanded the role of antihistamines in the treatment of allergic rhinitis. Certain patient populations, such as children and pregnant or lactating women, require special consideration regarding antihistamine choice and dosing as part of rhinitis therapy.

Improvement of effect of water-in-oil microemulsion as an oral delivery system for fexofenadine: in vitro and in vivo studies

Fexofenadine (FEX) has high solubility and low permeability (BCS, Class III). In this work, novel FEX loaded water in oil microemulsion (w/o) was designed to improve bioavailability and compared with Fexofen(®) syrup in in vitro and in vivo studies. In addition, pharmacokinetic parameters in permeability studies were estimated by using WinNonLin software program. w/o microemulsion system was optimized using a pseudoternary phase diagram, composed of span 80/lutrol F 68 (9.5:0.5 w/w), oleic acide, isopropyl alcohol and water as surfactant mixture; oil and cosurfactant was developed for oral drug delivery. w/o microemulsion systems were characterized by phase behavior, particle size, viscosity and solubilization capacity. In vitro studies were studied using Caco-2 cell monolayer. Pharmacokinetic parameters of w/o microemulsion were investigated in rabbits and compared to Fexofen(®) syrup. Fexofen(®) syrup and microemulsion were administered by oral gavage at 6 mg/kg of the same concentration. The experimental results indicated that microemulsion (HLB = 5.53) formed nanometer sized droplets (33.29 ± 1.76) and had good physical stability. This microemulsion increased the oral bioavailability of FEX which was highly water-soluble but fairly impermeable. The relative bioavailability of FEX microemulsion was about 376.76% compared with commercial syrup in rabbits. In vitro experiments were further employed for the enhanced effect of the microemulsion for FEX. These results suggest that novel w/o microemulsion plays an important role in enhancing oral bioavailability of low permeability drugs.

Pharmacologically active metabolites of currently marketed drugs: potential resources for new drug discovery and development

Biotransformation is the major clearance mechanism of therapeutic agents from the body. Biotransformation is known not only to facilitate the elimination of drugs by changing the molecular structure to more hydrophilic, but also lead to pharmacological inactivation of therapeutic compounds. However, in some cases, the biotransformation of drugs can lead to the generation of pharmacologically active metabolites, responsible for the pharmacological actions. This review provides an update of the kinds of pharmacologically active metabolites and some of their individual pharmacological and pharmacokinetic aspects, and describes their importance as resources for drug discovery and development.

Chronic urticaria: assessment of current treatment

Chronic urticaria is heterogenous, long-persisting and has a severe impact on quality of life and daily work. Effective treatment is essential but remains a confounding problem. This review summarizes available treatment strategies for chronic urticaria and their strength of evidence. Besides treatment of identified triggering factors such as chronic persistent bacterial infections (e.g., with Helicobacter pylori, streptococci, staphylococci or yersinia), standard treatment consists of nonsedating H1-antihistamines. Most patients require increasing (off-label) dosages that should be taken daily and regularly, however, this still fails in a third of cases. Reliable alternatives in the world literature are rare and the level of evidence is low. Certain subgroups may display benefit from additional treatment with cyclosporine A, cysteinyl leukotriene receptor antagonists, chloroquine, dapsone or other alternatives. A practicable step-wise treatment approach is given to optimize and individualize the treatment of patients with chronic urticaria.

Stereoselective synthesis of an active metabolite of the potent PI3 kinase inhibitor PKI-179

The synthesis and stereochemical determination of 1-(4-(4-((1R,5R,6R)-6-hydroxy-3-oxa-8-azabicyclo[3.2.1]octan-8-yl)-6-morpholino-1,3,5-triazin-2-yl)phenyl)-3-(pyridin-4-yl)urea (2), an active metabolite of the potent PI3 kinase inhibitor PKI-179 (1), is described. Stereospecific hydroboration of the double bond of 2,5-dihydro-1H-pyrrole 8 gave the 2,3-trans alcohol 9 exclusively. The configuration of the 3-hydroxyl group in 9 was inverted by an oxidation and stereoselective reduction sequence to give the corresponding 2,3-cis isomer 23. Both exo (21) and endo (27) isomers of the metabolite 2 were prepared via a practical synthetic route from 9 and 23, respectively, and the stereochemistry of 2 was determined to be endo. The endo isomer (27) was separated into two enantiomers 28 and 29 by chiral HPLC. Compound 2 was found to be enantiomerically pure and identical to the enantiomer 28. The absolute stereochemistry of the enantiomer 28 was determined by Mosher's method, thus establishing the stereochemistry of the active metabolite 2.

Fexofenadine: biochemical, pharmacokinetic and pharmacodynamic properties and its unique role in allergic disorders

BACKGROUND

Fexofenadine is one of several second-generation H(1)-antihistamines approved for the treatment of various allergic disorders; however, it shows numerous unique properties that make it an optimal choice for many patients.

OBJECTIVE

To review the pharmacology, efficacy and safety of fexofenadine and the attributes differentiating it from other H(1)-antihistamines.

METHODS

We performed a literature search in PubMed/MEDLINE (1966 - March 2009) using the keywords fexofenadine, antihistamine, allergic rhinitis and chronic urticaria. We also reviewed data provided by the manufacturer in addition to reports from various governmental agencies.

RESULTS/CONCLUSIONS

Fexofenadine is devoid of sedative and anticholinergic effects and may offer equivalent or greater efficacy in treating allergic disorders compared with other currently available second-generation H(1)-antihistamines. In addition, fexofenadine may offer cost savings over other selected H(1)-antihistamines owing to its recent availability in generic form in the US.

A review of the efficacy of desloratadine, fexofenadine, and levocetirizine in the treatment of nasal congestion in patients with allergic rhinitis

BACKGROUND

Nasal congestion is the most troublesome symptom of allergic rhinitis (AR). First-generation and older second-generation antihistamines, while effective against nasal itching, sneezing, and rhinorrhea, have limited efficacy in relieving nasal congestion.

OBJECTIVE

This review included nasal challenge studies and clinical trials that reported the effects on nasal congestion of the newer second-generation antihistamines desloratadine, fexofenadine, and levocetirizine.

METHODS

MEDLINE and EMBASE were searched for nasal challenge studies and clinical trials published in English between January 1, 1991, and January 31, 2009, using the following terms, alone or in combination: antihistamines, second-generation antihistamines, allergic rhinitis, intermittent allergic rhinitis, perennial allergic rhinitis, persistent allergic rhinitis, seasonal allergic rhinitis, nasal challenge, nasal blockage, and nasal congestion. Studies that were not active or placebo controlled, that did not evaluate change in nasal congestion scores, or that focused on treatments other than desloratadine, fexofenadine, and levocetirizine for nasal congestion associated with AR were excluded.

RESULTS

Twenty-six clinical trials met the criteria for inclusion in the review. In 11 placebo-controlled trials that included objective assessment of nasal congestion, desloratadine, fexofenadine, and levocetirizine were associated with reductions in the severity of nasal congestion through maintenance of nasal airflow. The mean AUC for nasal airflow over 6 hours was significantly greater with desloratadine compared with placebo in 3 studies (P < 0.05); placebo-controlled trials of fexofenadine and levocetirizine had similar results. In 25 placebo- and active-controlled trials that reported subject-rated symptom scores, the 3 newer antihistamines were efficacious in the treatment of nasal congestion associated with AR. In 10 trials that reported objective and/or subjective measures, desloratadine was associated with significant improvements in nasal congestion compared with placebo (P < or = 0.05), beginning as early as the first 2 hours after allergen challenge. Fexofenadine was associated with significantly lower nasal congestion scores compared with placebo in 4 studies (P <- 0.05); nasal congestion scores were significantly reduced with levocetirizine in 3 placebo-controlled trials (P < or = 0.005).

CONCLUSIONS

In the studies reviewed, desloratadine, fexofenadine, and levocetirizine were effective in relieving the nasal congestion associated with AR compared with placebo. This effect began as early as day 2 and was consistent and progressive throughout treatment. Desloratadine, fexofenadine, and levocetirizine are appropriate options for the treatment of nasal congestion in patients with AR.

Comparison of the efficacy and safety of bilastine 20 mg vs desloratadine 5 mg in seasonal allergic rhinitis patients

BACKGROUND

Bilastine is a novel, nonsedating H(1)-antihistamine developed for symptomatic treatment of Allergic Rhinitis and Chronic Idiopathic Urticaria. The objective of this study was to compare the efficacy and safety of bilastine 20 mg vs placebo and desloratadine 5 mg in subjects with seasonal allergic rhinitis (SAR).

METHODS

This randomized, double blind, placebo-controlled, parallel-group multicentre study evaluated the effect of 2 weeks' treatment with bilastine 20 mg, desloratadine 5 mg or matched placebo once daily, in 12-70 years old symptomatic SAR patients. All subjects assessed the severity of nasal (obstruction, rhinorrhoea, itching, and sneezing) and nonnasal (ocular itching, tearing, ocular redness, itching of ears and/or palate) symptoms on a predetermined scale to provide a total symptom score (TSS), composed of nasal and nonnasal symptom scores (NSS and NNSS, respectively). The primary efficacy measure was the area under the curve (AUC) for the TSS over the entire treatment period.

RESULTS

Bilastine 20 mg significantly reduced the AUC of TSS to a greater degree from baseline compared to placebo (98.4 with bilastine vs 118.4 with placebo; P < 0.001), but not compared to desloratadine 5 mg (100.5). Bilastine 20 mg was not different from desloratadine 5 mg but significantly more effective than placebo in improving the NSS, NNSS, and rhinitis-associated discomfort scores (P < 0.05), and rhinoconjunctivitis quality of life questionnaire total (P < 0.005) and four out of seven individual domain (P < 0.05) scores. The incidence of treatment emergent adverse events was similar for bilastine (20.6%), desloratadine (19.8%), and placebo (18.8%).

CONCLUSION

Bilastine 20 mg once daily was efficacious, safe and not different from desloratadine 5 mg once daily in the treatment of SAR symptoms.

H1 antihistamines: current status and future directions

In this review, we compare and contrast the clinical pharmacology, efficacy, and safety of first-generation H1 antihistamines and second-generation H1 antihistamines. First-generation H1 antihistamines cross the blood-brain barrier, and in usual doses, they potentially cause sedation and impair cognitive function and psychomotor performance. These medications, some of which have been in use for more than 6 decades, have never been optimally investigated. Second-generation H1 antihistamines such as cetirizine, desloratadine, fexofenadine, levocetirizine, and loratadine cross the blood-brain barrier to a significantly smaller extent than their predecessors. The clinical pharmacology, efficacy, and safety of these medications have been extensively studied. They are therefore the H1 antihistamines of choice in the treatment of allergic rhinitis, allergic conjunctivitis, and urticaria. In the future, clinically advantageous H1 antihistamines developed with the aid of molecular techniques might be available.