An Evaluation of the Antihistamine Activity of Acrivastine and Its Onset in Human Skin

In a double-blind, two-period crossover study, 24 healthy volunteers were evaluated to establish the time of onset of action of activity of acrivastine in suppressing the weal and flare response to intradermally injected histamine. Volunteers received single doses of 8 mg acrivastine and placebo according to a fully randomized, balanced treatment plan. Acrivastine significantly ( P < 0.002) reduced the flare response induced by 0.4 μg histamine challenge 15 min after oral acrivastine dosing when compared with placebo. A significant ( P < 0.001) reduction of the weal response was noted at 25 min, although trends in this direction were already present at earlier time points.

Dans d'une étude croisée à deux phase, réalisée en double aveugle et ayant porté sur 24 volontaires sains, on a tenté d'établir le moment du début de l'action de l'acrivastine dans la suppression de la réponse inflammatoire consécutive à l'injection intradermique d'histamine. Les volontaires ont reçu des doses uniques de 8 mg d'acrivastine et de placebo, selon un plan de traitement entièrement randomisé et équilibré. L'acrivastine a réduit significativement ( P < 0,002) la réponse de rubéfaction induite par 0,4 μg d'histamine 15 minutes après l'administration orale d'acrivastine, par rapport au placebo. Une réduction significative ( P < 0,001) de la réponse d'enflure a été notée à 25 minutes, bien qu'une tendance en ce sens ait déjà été observée à un stade plus précoce.

Development and validation of a rapid stability indicating HPLC-method using monolithic stationary phase and two spectrophotometric methods for determination of antihistaminic acrivastine in capsules

Simple, rapid and accurate high performance liquid chromatographic (HPLC) and spectrophotometric methods are described for determination of antihistaminic acrivastine in capsules. The first method (method A) is based on accurate, sensitive and stability indicating chromatographic separation method. Chromolith® Performance RP-18e column, a relatively new packing material consisting of monolithic rods of highly porous silica, was used as stationary phase applying isocratic binary mobile phase of ACN and 25 mM NaH2PO4 pH 4.0 in the ratio of 22.5:77.5 at flow rate of 5.0 mL/min and 40°C. A diode array detector was used at 254 nm for detection. The elution time of acrivastine was found to be 2.080±0.032. The second and third methods (methods B and C) are based on the oxidation of acrivastine with excess N-bromosuccinimide (NBS) and determination of the unconsumed NBS with, metol-sulphanilic acid (λmax: 520 nm) or amaranth dye (λmax: 530 nm). The reacted oxidant corresponds to the drug content. Beer's law is obeyed over the concentration range 1.563-50, 2.0-20 and 1.0-10 μg mL(-1) for methods A, B and C, respectively. The limits of detection and quantitation were 0.40, 0.292 and 0.113 μg mL(-1) and 0.782, 0.973 and 0.376 μg mL(-1) for methods A, B and C, respectively. The HPLC method was validated for system suitability, linearity, precision, limits of detection and quantitation, specificity, stability and robustness. Stability tests were done through exposure of the analyte solution for four different stress conditions and the results indicate no interference of degradants with HPLC-method. The proposed methods was favorably applied for determination of acrivastine in capsules formulation. Statistical comparison of the obtained results from the analysis of the studied drug to those of the reported method using t- and F-tests showed no significant difference between them.

Analogues of Triprolidine: Structural Influences upon Antihistamine Activity

The synthesis of some geometrical isomers related to triprolidine is reported. Previous configurational assignments, by UV and proton NMR, are validated by high field nuclear Overhauser enhancement methods and the isomeric purity of tested E- and Z-isomers was greater than 99.5% as assessed by an HPLC method developed for these compounds. Affinity constants for triprolidine (E and Z) in guinea-pig ileum showed a potency ratio of ∼600 whereas at cerebellar sites this ratio was only ∼100, suggesting that the H1 receptor in these two tissues may not be identical. In-vivo tests using a lethal dose of compound 48/80 (a potent histamine-releasing agent) demonstrated that triprolidine itself was the most active compound to protect the animal among all the isomeric compounds tested: in all isomeric pairs the E-configuration possessed superior activity over Z. The disposition of the aryl groups in these geometrically constrained compounds mimics that seen in the structurally related chiral pheniramines which are sp3 hybridized and whose absolute stereochemistry is known.

Quantification of antihistamine acrivastine in plasma by solid-phase extraction and high-performance liquid chromatography

An automated solid-phase extraction method was developed for the determination of the H1-antihistamine acrivastine in plasma samples. Acrivastine was analyzed at the wavelength of 254 nm using a reversed-phase HPLC assay. Both extraction procedure and analytical condition were optimized and validated for maximum recovery and resolution. The developed method was further applied to plasma samples collected from an in vivo pharmacokinetic study in rabbits. The assay was found to be simple, specific, accurate and reproducible.

Spectrophotometric determination of some antihistaminic drugs using 7,7,8,8-tetracyanoquinodimethane (TCNQ)

A simple and sensitive spectrophotometric method is suggested for analysis of 3 antihistaminic drugs, acrivastine (I), mequitazine (II), and dimethindene maleate (III). The method is based on reaction of the drugs with 7,7,8,8-tetracyanoquinodimethane (TCNQ) in acetonitrile to form highly stable colored products that are measured at 750, 766, and 844 nm for I and II, and 480 and 618 nm for III. Beer's law is obeyed in the ranges of 5-60 microg/mL for 1, 5-50 microg/mL for II, and 10-70 microg/mL for III. The optimum assay conditions and their applicability to the determination of the cited drugs in pharmaceutical formulations are described. The method is statistically analyzed as compared with the European Pharmacopoeia (2001) method for the analysis of dimethindene maleate and reference methods for acrivastine and mequitazine drugs revealing good accuracy and precision.

The butterbur extract petasin has no effect on skin test reactivity induced by different stimuli: a randomized, double-blind crossover study using histamine, codeine, methacholine, and aeroallergen solutions

BACKGROUND

Petasin (Ze 339) was recently introduced on the market as a potent herbal antiallergic drug for treatment of respiratory allergies such as hay fever. Few clinical studies have been performed so far addressing the clinical effectiveness of Ze 339.

OBJECTIVE

To evaluate the antiallergic properties of Ze 339 using skin prick tests with different stimuli, such as codeine, histamine, methacholine, and a relevant inhalant allergen.

METHODS

A randomized, double-blind, placebo-controlled study was performed in which Ze 339 was compared to acrivastine, a short-acting antihistamine, in 8 patients with respiratory allergy and in 10 nonatopic, healthy volunteers. Antiallergic activity of Ze 339 was determined by analyzing inhibitory potency in skin prick tests with codeine, histamine, methacholine, and an inhalant allergen. Wheal-and-flare reactions were assessed 90 minutes after a double dose of Ze 339, acrivastine, or placebo. An interval of at least 3 days was left between the skin tests.

RESULTS

Acrivastine was identified as the only substance that significantly inhibited skin test reactivity to all solutions analyzed in all study subjects. In contrast, no significant inhibition could be demonstrated for Ze 339 with any test solution. Moreover, the results of Ze 339 did not differ significantly from placebo.

CONCLUSIONS

In this study we found no antiallergic, particularly antihistaminic, effect of Ze 339 in skin tests using a variety of stimuli often used to evaluate immediate skin test reactivity. The mechanism by which Ze 339 is effective in the treatment of seasonal allergic rhinitis still needs to be elucidated.

Evaluation and comparison of five matrix excipients for the controlled release of acrivastine and pseudoephedrine

For treatment of allergic rhinitis, acrivastine with pseudoephedrine in Semprex-D conventional capsules requires dosing every 6-8 hours. This study was designed to develop a controlled release matrix tablet of acrivastine and pseudoephedrine and evaluate 5 different matrix excipients for their in vitro controlled-release profiles. Compritol 888ATO, Eudragit RS, Methocel K100M, Polyox WSR301 and Precirol ATO5 were used alone or in varying combinations for the formulation of controlled release matrix tablets. In vitro drug dissolution and mathematical modeling were used to characterize drug release rate and extent. All tablet formulations yielded quality matrix preparations with satisfactory tableting properties. Due to the aqueous solubility of pseudoephedrine and the size of the dose, none of the matrix excipients used alone prolonged drug release significantly to meet the desired twice-daily administration frequency. The use of two excipients in combination, however, significantly decreased the dissolution rate of both active ingredients. A combined lipid-based Compritol and hydrophilic Methocel produced optimal controlled drug release for longer than 8 hours for both acrivastine and pseudoephedrine.

Simultaneous analysis of the H1-antihistamine acrivastine and the decongestant pseudoephedrine hydrochloride by high-performance liquid chromatography

High-performance liquid chromatography (HPLC) was used for the simultaneous quantification of the H(1)-antihistamine acrivastine and the decongestant pseudoephedrine hydrochloride. Both compounds were detected at the wavelength of 214 nm. The influence of the mobile phase and the detection wavelength was evaluated and optimized. This method was used to assay various samples from studies of the commercial preparation Semprex-D capsules. The method was found to be accurate, specific, selective, rapid, and versatile for use in routine quality control analyses.

Homology modelling and binding site mapping of the human histamine H1 receptor

Three-dimensional model of the human histamine H1 receptor was developed by homology modelling using the high resolution structure of bovine rhodopsin as template. Genetic algorithm based docking calculations were used to identify the role of several amino acids having an effect on agonist or antagonist binding. Binding mode analyses of mepyramine, desloratidine, loratidine and acrivastine allowed us to rationalise their binding affinity. Binding site mapping resulted in seven new potential aromatic interaction points (Tyr 108, Phe 184, Phe 190, Phe 199, Phe 424, Trp 428, Tyr 431), that took part in forming the lipophilic pocket of the antagonist binding cavity.

Zafirlukast has no beneficial effects in the treatment of chronic urticaria

BACKGROUND

Leukotriene receptor antagonists have shown some efficacy in t he treatment of asthma. Injection of LTC4, LTD4 and LTE4 into the skin leads to a weal-and-flare reaction, suggesting an involvement of leukotrienes in the pathogenesis of urticaria. Indeed, various reports have indicated a beneficial effect for leukotriene receptor antagonists in patients with chronic urticaria.

OBJECTIVE

To determine the therapeutic effect of the leukotriene receptor antagonist zafirlukast in patients with chronic urticaria.

METHODS

The study was a double-blind, placebo-controlled, cross-over study lasting for 12 weeks. Fifty-two patients with chronic urticaria were investigated at a university hospital. The patients were randomized to receive 20 mg zafirlukast b.i.d. or placebo and cross-over was scheduled after 6 weeks. The efficacy of the treatment was evaluated by a daily symptom score, six physical examinations, the requirement of rescue antihistamines (acrivastine) and an overall assessment by the patient andthe investigating physician.

RESULTS

Forty-six patients completed the study: zafirlukast was well tolerated without alteration of the investigated laboratory parameters. In comparison with placebo, treatment with zafirlukast resulted in no significant positive effect for any of the efficacy measures. Moreover, we were unable to identify any subgroup of patients with chronic urticaria responding with a therapeutic benefit.

CONCLUSIONS

The leukotriene receptor antagonist zafirlukast does not provide a significant therapeutic benefit at a dose of 20 mg b.i.d. in patients with chronic urticaria.

Electrochemical behaviour and determination of acrivastine in pharmaceuticals and human urine

The differential pulse polarography, DC-tast polarography and cyclic voltammetry behaviour of acrivastine was studied in Britton-Robinson buffer solutions (pH 2-11.7). In acidic media, a non-reversible diffusion controlled reduction process involving four electrons takes place. Two reduction waves appear at a E(1/2)=-0.6 and -0.99 V. The reduction mechanism is discussed. The linear relationship between peak current height and acrivastine concentration allowed the differential pulse polarographic determination of acrivastine over a wide concentration range, from 0.35 to 26.1 mg l(-1)at pH 2.5. The procedure was applied to determination of the drug in pharmaceutical formulations and human urine samples.

Cardiotoxicity of new antihistamines and cisapride

Although the new second-generation nonsedative antihistamines terfenadine and astemizole were launched as highly selective and specific H(1)-receptor antagonists, they were later found to cause prolongation of the QT-interval and severe cardiac arrhythmias. The prolongation of the QT-interval is caused by the blockade of one or more of the cardiac potassium channels, among which the delayed rectifier I(Kr), encoded by the HERG-gene, appears to be the most significant. The potency of the prokinetic drug cisapride to block I(Kr) appears to be similar to that of terfenadine (IC(50) about 50 nmol/l). These drugs cause problems when overdosed, used in combination with inhibitors of their CYP3A4-mediated metabolism, or when given to individuals with altered drug kinetics (the aged) or patients with existing cardiac disease (congenitally long QT). Moreover, interactions with other QT-interval prolonging drugs require special attention. Active hydrophilic metabolites of the second-generation antihistaminic compounds (ebastine-carebastine, loratadine-desloratadine, terfenadine-fexofenadine, astemizole-norastemizole) are new compounds with probably reduced risk for drug interactions and cardiac toxicity.

Lipophilicity behaviour of the Zwitterionic antihistamine cetirizine in phosphatidylcholine liposomes/water systems

PURPOSE

The partitioning of cetirizine in a phosphatidylcholine liposomes/water system was compared with that of hydroxyzine and acrivastine to gain insight into the mechanisms of interaction of its various electrical species with membranes.

METHODS

The lipophilicity profiles of the compounds were obtained from equilibrium dialysis and potentiometry, and compared with changes in NMR relaxation rates.

RESULTS

The neutral form of hydroxyzine interacted mainly via hydrophobic interactions with the bilayer lipid core of the membrane, whereas for the cationic form both hydrophobic and electrostatic interactions were involved. Zwitterionic and anionic cetirizine were less lipophilic than its cation, which behaved like the corresponding species of hydroxyzine. Zwitterionic cetirizine interacted more by weak electrostatic interactions with the polar headgroups of phospholipids than by hydrophobic interactions with the membrane interior. The lipophilicity of its anion reflected the balance of repulsive electrostatic interactions between the carboxylate and phosphate groups and the hydrophobic interactions with the lipid core.

CONCLUSION

The study confirms that various mechanisms influence the interaction of solutes with liposomes. Combining experimental techniques and using suitable reference compounds proves useful.

Sedation with "non-sedating" antihistamines: four prescription-event monitoring studies in general practice

OBJECTIVES

To investigate the frequency with which sedation was reported in post-marketing surveillance studies of four second generation antihistamines: loratadine, cetirizine, fexofenadine, and acrivastine.

DESIGN

Prescription-event monitoring studies.

SETTING

Prescriptions were obtained for each cohort in the immediate post-marketing period.

SUBJECTS

Event data were obtained for a total of 43 363 patients.

MAIN OUTCOME MEASURES

Reporting of sedation or drowsiness.

RESULTS

The odds ratios (adjusted for age and sex) for the incidence of sedation were 0.63 (95% confidence interval 0.36 to 1.11; P=0.1) for fexofenadine; 2.79 (1.69 to 4.58; P<0.0001) for acrivastine, and 3.53 (2.07 to 5.42; P<0.0001) for cetirizine compared with loratadine. No increased risk of accident or injury was evident with any of the four drugs.

CONCLUSIONS

Although the risk of sedation was low with all four drugs, fexofenadine and loratadine may be more appropriate for people working in safety critical jobs.

Onset-of-action for antihistamine and decongestant combinations during an outdoor challenge

BACKGROUND

Medications containing a combination antihistamine-decongestant are commonly used for allergic rhinitis yet onset-of-action comparisons for symptom relief after a single dose have not been performed.

OBJECTIVE

To determine the onset of symptom relief and efficacy of antihistamine-decongestant medications (acrivastine-pseudoephedrine and loratadine-pseudoephedrine) compared with placebo in an outdoor park.

METHODS

This study was conducted during the spring of 1997 using a double-blind, placebo-controlled design. Patients completed baseline rhinitis symptom diaries from 7:30 to 9:30 AM. Subjects with qualifying symptom scores received one dose of either acrivastine-pseudoephedrine, loratadine-pseudoephedrine, or placebo at 10:00 AM. Symptom diaries were recorded for the next 4 hours.

RESULTS

Of 593 patients randomized to treatment, 592 were included in efficacy analysis. Acrivastine-pseudoephedrine and loratadine-pseudoephedrine demonstrated a mean onset-of-action by 45 and 30 minutes respectively for total symptom and rhinitis symptom scores for the five sites. Onset-of-action for nasal congestion scores was 45 minutes for both medications. Sites having higher pollen exposure (>100 pollen grains over 6 hours) demonstrated a difference between the antihistamine combinations: acrivastine-pseudoephedrine had an onset of action at 45 minutes for total symptom and rhinitis symptom scores, and 15 minutes for nasal congestion scores whereas loratadine-pseudoephedrine had onset-of-action for nasal congestion score of 105 minutes but failed to reach significance at any timepoint for total symptom and rhinitis symptom scores.

CONCLUSIONS

Both antihistamine-decongestant combinations demonstrate an onset-of-action within 60 minutes of administration but under conditions of higher pollen exposure, the acrivastine combination was more effective for total symptoms, rhinitis symptoms, and nasal congestion with an onset-of-action within 45 minutes for rhinitis symptoms and 15 minutes for congestion.

Inhibition of histamine or allergen-induced wheals by a single dose of acrivastine, fexofenadine or cetirizine

Certirizine, a potent H1-blocking agent, is often recommended as an emergency drug in anaphylactic reactions because of its well documented fast onset of action. In this randomized, cross-over study we compared the onset of action after a single dose of two recently introduced antihistamines, acrivastine and fexofenadine, with that of cetirizine. The inhibition of the wheal-and-flare reaction produced by skin prick test with histamine in 20 healthy volunteers and with a relevant pollen allergen in 20 atopic patients, respectively, were measured before and at regular intervals up to 60 min after the ingestion of acrivastine (8 mg and 16 mg), fexofenadine (120 mg) and cetirizine (10 mg and 20 mg). Wheal-and-flare reaction were significantly inhibited 20 min after the intake of 16 mg acrivastine in atopic patients and 30 min after intake of 8 mg acrivastine in healthy volunteers, whereas cetirizine produced a significant inhibition of the wheal-and-flare reaction within 40-60 min. No significant inhibition could be observed within 60 min after fexofenadine intake. Therefore, in clinical settings when a fast onset of the H1-blocking action is mandatory (e.g., after insect stings or for short-term prophylaxis) we recommend acrivastine.

Mutational analysis of the antagonist-binding site of the histamine H(1) receptor

We combined in a previously derived three-dimensional model of the histamine H(1) receptor (Ter Laak, A. M., Timmerman, H., Leurs, H., Nederkoorn, P. H. J., Smit, M. J., and Donne-Op den Kelder, G. M. (1995) J. Comp. Aid. Mol. Design. 9, 319-330) a pharmacophore for the H(1) antagonist binding site (Ter Laak, A. M., Venhorst, J., Timmerman, H., and Donné-Op de Kelder, G. M. (1994) J. Med. Chem. 38, 3351-3360) with the known interacting amino acid residue Asp(116) (in transmembrane domain III) of the H(1) receptor and verified the predicted receptor-ligand interactions by site-directed mutagenesis. This resulted in the identification of the aromatic amino acids Trp(167), Phe(433), and Phe(436) in transmembrane domains IV and VI of the H(1) receptor as probable interaction points for the trans-aromatic ring of the H(1) antagonists. Subsequently, a specific interaction of carboxylate moieties of two therapeutically important, zwitterionic H(1) antagonists with Lys(200) in transmembrane domain V was predicted. A Lys(200) --> Ala mutation results in a 50- (acrivastine) to 8-fold (d-cetirizine) loss of affinity of these zwitterionic antagonists. In contrast, the affinities of structural analogs of acrivastine and cetirizine lacking the carboxylate group, triprolidine and meclozine, respectively, are unaffected by the Lys(200) --> Ala mutation. These data strongly suggest that Lys(200), unique for the H(1) receptor, acts as a specific anchor point for these "second generation" H(1) antagonists.

Effects of acrivastine, loratadine and cetirizine on histamine-induced wheal and flare responses

It is accepted that studies evaluating histamine-induced wheal and flare reactions in the skin represent a simple and reliable method for demonstrating pharmacodynamic activity and pharmacokinetics of the H1-receptor antagonists. In this study, the effects of single oral doses of acrivastine (8 mg), loratadine (10 mg) and cetirizine (10 mg) on the histamine-induced wheal and flare reactions were compared in 60 healthy volunteers. The wheal and flare responses were produced by prick test using 1% histamine solution. Measurements were performed before the ingestion of antihistamines (baseline values) and afterwards at 15, 30, 90, 240, 360 min and 24 h. The values obtained for each antihistamine were compared with each other and with baseline values. Cetirizine was found to be superior to acrivastine and loratadine for the suppression of wheal and flare responses at 240, 360 min and 24 h (P < 0.05) and acrivastine was superior to the other two antihistamines for the suppression of flare response at 30 min (P < 0.05). Our results indicate that a single dose of cetirizine provides a more effective and long acting suppression on wheal and flare reactions in urticaria when compared to acrivastine and loratadine.

Variations among non-sedating antihistamines: are there real differences?

Most of the modern non-sedating H1 receptor antagonists (antihistamines) penetrate the brain poorly, allowing the use of doses large enough to counteract allergic processes in peripheral tissues without important central effects. The antihistamines reviewed here are acrivastine, astemizole, cetirizine, ebastine, fexofenadine, loratadine, mizolastine, and terfenadine. However, these drugs are not entirely free from central effects, and there are at least quantitative differences between them. Although psychomotor and sleep studies in healthy subjects in the laboratory may predict that an antihistamine does not cause drowsiness, the safety margin can be narrow enough to cause a central sedating effect during actual treatment. This might result from a patient's individual sensitivity, disease-induced sedation, or drug dosages that are for various reasons relatively or absolutely larger (patient's weight, poor response, reduced drug clearance, interactions). Mild to even moderate sedation is not necessarily a major nuisance, particularly if stimulants need be added to the regimen (e.g. in perennial rhinitis). Furthermore, patients can adjust doses themselves if needed. Sedating antihistamines are not needed for long-term itching, because glucocorticoids are indicated and more effective. It is wise to restrict or avoid using antihistamines (astemizole, terfenadine) that can cause cardiac dysrhythmias, because even severe cardiotoxicity can occur in certain pharmacokinetic drug-drug interactions. Histamine H1 receptor antagonists (antihistamines) are used in the treatment of allergic disorders. The therapeutic effects of most of the older antihistamines were associated with sedating effects on the central nervous system (CNS) and antimuscarinic effects causing dry mouth and blurred vision. Non-specific "quinidine-like" or local anaesthetic actions often led to cardiotoxicity in animals and man. Although such adverse effects varied from drug to drug, there was some degree of sedation with all old antihistamines. Non-sedating antihistamines have become available during the past 15 years. Some of them also have antiserotonin or other actions that oppose allergic inflammation, and they are not entirely free from sedative effects either. In small to moderate "clinical" concentrations they are competitive H1 receptor antagonists, although large concentrations of some of them exert non-competitive blockade. Daytime drowsiness and weakness are seldom really important, and they restrict patients' activities less than the old antihistamines. Some new antihistamines share with old antihistamines quinidine-like effects on the cardiac conducting tissues, and clinically significant interactions have raised the question of drug safety. This prodysrhythmic effect has also been briefly mentioned in comparisons of non-sedative H1 antihistamines.

Risk of ventricular arrhythmias associated with nonsedating antihistamine drugs

AIMS

To quantify and compare the incidence of ventricular arrhythniias associated with the use of five nonsedating antihistamines: acrivastine, astemizole, cetirizine, loratadine and terfenadine. The effects of age, sex, dose, duration of treatment, and the interaction with P450 inhibitor drugs were also examined.

METHODS

We carried out a cohort study with a nested case-control analysis using the UK-based General Practice Research database (GPRD). The study cohort included persons aged less than 80 years old who received their first prescription for any of the five study drugs between January 1, 1992 and September 30, 1996. We estimated relative risks and 95% confidence intervals of idiopathic ventricular arrhythmias with current use of antihistamines as compared with non use.

RESULTS

The study cohort included 197425 persons who received 513012 prescriptions. Over the study period 18 valid cases of idiopathic ventricular arrhythmias were detected. Nine occurred during the current use of any antihistamine, resulting in a crude incidence of 1.9 per 10000 person-years (95%CI: 1.0-3.6) and a relative risk of 4.2 (95%CI: 1.5-11.8) as compared with non use. Astemizole presented the highest relative risk (RR= 19.0; 95%CI: 4.8-76.0) of all study drugs, while terfenadine (RR=2.1; 95%CI:0.5-8.5) was in the range of other nonsedating antihistamines. Older age was associated with a greater risk of ventricular arrhythmias (RR=7.4; 95%CI: 2.6-21.4) and seemed to increase the effect of antihistamines (RR=6.4; 95%CI: 1.7-24.8). The proportions of high dose terfenadine and the concomitant use with P450 inhibitors among current users of terfenadine were 2.7% and 3.4%, respectively over the study period with no single case of ventricular arrhythmias occurring in the presence of these two risk factors.

CONCLUSIONS

The use of nonsedating antihistamines increases the risk of ventricular arrhythmias by a factor of four in the general population. Yet, the absolute effect is quite low requiring 57000 prescriptions, or 5300 person-years of use for one case to occur. The risk associated with terfenadine was no different from that with other nonsedating antihistamines.

Quantitative determination of acrivastine and pseudoephedrine hydrochloride in pharmaceutical formulation by high performance liquid chromatography and derivative spectrophotometry

In this study, fourth derivative spectrophotometry and high performance liquid chromatography (HPLC) have been used and described for the quantitative determination of acrivastine (I) and pseudoephedrine hydrochloride (II) in their pharmaceutical capsules form (Duact). In the former method, d4A/d gamma 4 values were measured in methanol at 315 and 269 nm for (I) and (II) respectively. The relative standard deviations (RSD) for the method were found to be 1.16% for (I) and 0.94% for (II). The latter method based on reversed phase HPLC system using LiChrosorb C18 analytical column. The mobile phase used for separation of (I), (II) and internal standard (p-hydroxymethylbenzoate) were the water/acetonitrile/methanol/perchloric acid/n-octylamine (500:130:25:13:0.3 v/v) and the detection of the compounds in the capsules were at 260 nm using UV detector. The RSD for the HPLC method were determined to be 0.79 and 0.88% for (I) and (II) respectively. The proposed methods, which give thoroughly comparable data, are simple, rapid, and allow precise and accurate results and could be used for commercial formulations containing acrivastine and pseudoephedrine hydrochloride in combination.

Blocking effects of promethazine, triprolidine and their analogues on the excitation caused by the peptide, achatin-I

An Achatina endogenous tetrapeptide, achatin-I (Gly-D-Phe-Ala-Asp), applied by brief pressure, produced an inward current (Iin) on an Achatina giant neurone type, PON (periodically oscillating neurone). Promethazine, triprolidine and their analogues tested, applied by perfusion, showed a tendency to inhibit the Iin, suggesting that the effective structures vary to a wide extent. With respect to promethazine and its analogues, the presence of 2-bromo, 5-oxo, 3-dimethylsulfamido and 2-methoxy weakened the effects. 10-(2-methylamino-2-methylethyl) instead of 10-(2-dimethylamino-2-methylethyl) of promethazine and the azepine ring instead of phenothiazine ring potentiated the effects. From the dose (pressure duration)-response study of achatin-I, the two promethazine analogues, RP 6497 and RP 6549 (the structures are shown in Fig. 1), inhibited the Iin in partly competitive and partly noncompetitive manners. Regarding triprolidine and its analogues, the compounds in Z-configuration seemed to be more effective than those in E-configuration. The presence of 4-methyl in 1-phenyl, and 1-(4-pyridyl) instead of 1-(2-pyridyl) potentiated the effects. 3-Dimethylamino instead of 3-pyrrolidino weakened the effects. The two triprolidine analogues, Trip Der 3 and Trip Der 6 (the structures in Fig. 2), inhibited the Iin in an uncompetitive manner.

Efficacy of acrivastine plus pseudoephedrine for symptomatic relief of seasonal allergic rhinitis due to mountain cedar

BACKGROUND

Acrivastine is a second-generation H1-antagonist chemically related to triprolidine, but more polar and with less central nervous system penetration than triprolidine.

OBJECTIVE

The efficacy of the antihistamine-decongestant combination product (Semprex-D capsules) containing acrivastine 8 mg plus pseudoephedrine HCl 60 mg was evaluated for the treatment of seasonal allergic rhinitis symptoms.

METHODS

A total of 676 patients sensitive to mountain cedar pollen was enrolled into a 6-center, randomized, double-blind, placebo-controlled, parallel, 4-group study designed to compare acrivastine + pseudoephedrine, acrivastine, pseudoephedrine, and placebo. Patients with demonstrable diary symptom scores at baseline took study medication (4 doses/day) and recorded symptom scores twice daily for 2 weeks. The effectiveness of the acrivastine + pseudoephedrine combination was examined relative to the individual components and placebo in terms of changes in diary symptom scores.

RESULTS

Over the 2-week period, the combination of acrivastine plus pseudoephedrine was significantly more effective than (1) acrivastine, pseudoephedrine, and placebo (P < .001) for relief of all symptoms; (2) pseudoephedrine (P < .001) for relieving allergy symptoms, ie, running nose, sneezing, itchy nose/throat and tearing; and (3) acrivastine (P < .001) for reducing nasal congestion. Relative to placebo, small increases in adverse experience rates were observed with acrivastine + pseudoephedrine for dry mouth, insomnia, somnolence, and headache.

CONCLUSION

These findings in a large clinical trial demonstrate (1) the efficacy of acrivastine and (2) that each component of the combination of acrivastine 8 mg plus pseudoephedrine HCl 60 mg contributes to the overall efficacy, thereby supporting the conclusion that the combination is rational, safe, and effective for the treatment of allergic rhinitis.

Effects of semprex-D and diphenhydramine on learning in young adults with seasonal allergic rhinitis

OBJECTIVES

The purpose of this study was to test the hypothesis that learning ability is impaired in patients with seasonal allergic rhinitis relative to untreated individuals and to evaluate a combination compound (acrivastine 8 mg + pseudoephedrine 60 mg) for attenuation of the learning impairment in these patients.

BACKGROUND

In a previous study employing the same method it was shown that young children (10 to 12 yrs) suffering from seasonal allergic rhinitis performed significantly worse on tests of learning and using knowledge after acute treatment with a sedating antihistamine (diphenhydramine 50 mg) or placebo as compared with nontreated healthy controls. This effect was partially reversed by treatment with loratadine.

METHODS

Sixty-seven young adults suffering from seasonal allergic rhinitis and 28 matched controls were trained on didactic simulation for three consecutive days. Atopic subjects were treated differentially during training according to a double-blind, randomized, parallel group design with either diphenhydramine hydrochloride 50 mg, a combination compound (acrivastine 8 mg + pseudoephedrine 60 mg, A + P), or placebo, administered qd. After training, all atopic subjects were maintained on A + P treatment for 14 days at which time all groups returned for examination.

RESULTS

Mean performance at the end of training was worse for all atopic subjects combined compared with normal subjects. Subjects treated with diphenhydramine performed significantly worse than either normals (P < .001) or those treated with A + P (P < .001). At the examination, the diphenhydramine group's performance differed significantly from those of the normal (P < .001) and A + P groups (P < .001).

CONCLUSION

The study supports our previous finding that allergy symptoms reduce learning ability which is further reduced learning ability which is further reduced by diphenhydramine. Atopic subjects with allergies treated with acrivastine + pseudoephedrine learned as well as normal subjects.

Efficacy of acrivastine with pseudoephedrine in treatment of allergic rhinitis due to ragweed

BACKGROUND

Semprex-D capsules contain acrivastine 8 mg (a second generation H1-antagonist) plus pseudoephedrine HCl 60 mg and were developed to satisfy the needs of allergy suffers who prefer combination products designed to provide broader symptom relief. Approval of combination products by the US Food and Drug Administration requires demonstration that each component contributes to the overall effectiveness.

OBJECTIVE

The objective of the study was to demonstrate that both acrivastine and pseudoephedrine share in the efficacy of the combination in relieving allergy symptoms in patients sensitive to ragweed pollen.

METHODS

This was a double-blind, randomized, placebo-controlled, parallel groups, balanced design, multicenter (13 sites) study. Patients 12 years of age or older with skin test reactivity to ragweed were recruited. Patients who qualified for the study were dispensed either (1) acrivastine + pseudoephedrine, (2) acrivastine, (3) pseudoephedrine, or (4) placebo with instructions to take one capsule 4 times daily and to record allergy symptom scores in a symptom diary 3 times daily for 14 days. Assessments of health, global allergy symptoms, protocol compliance, adverse events, and vital signs were also documented.

RESULTS

A total of 702 patients were enrolled in this study. Over the 2-week period, the combination of acrivastine + pseudophedrine was significantly more effective than acrivastine, pseudoephedrine, and placebo for relief of all symptoms (P range .01 to .001); pseudoephedrine for treating symptoms responsive to antihistamines (P = .003); and acrivastine for treating symptoms responsive to nasal decongestants (P < .001). Relatively small increases in adverse experience rates were observed for the combination relative to the placebo.

CONCLUSIONS

These findings in a large clinical trial demonstrate that each component of the combination of acrivastine 8 mg plus pseudoephedrine HCl 60 mg contributes to the overall efficacy, thereby supporting the conclusion that the combination is rational, safe, and effective for the treatment of allergic rhinitis.

Antihistamine effects on actual driving performance in a standard test: a summary of Dutch experience, 1989-94

The review summarizes the major results of eight double-blind, placebo-controlled, volunteer studies undertaken by three independent institutions for showing the effects on actual driving performance of "sedating" and "nonsedating" antihistamines (respectively, triprolidine, diphenhydramine, clemastine and terfenadine, loratadine, cetirizine, acrivastine, mizolastine, and ebastine). A common, standardized test was used that measures driving impairment from vehicular "weaving" (i.e., standard deviation of lateral position (SDLP)). Logical relationships were found between impairment and dose, time after dosing, and repeated doses over 4-5 days. The newer drugs were generally less impairing, but differences existed among their effects, and none was unimpairing at doses 1-2x the currently recommended levels. One or possibly two of the newer drugs possessed both performance-enhancing and -impairing properties, depending on dose, suggesting two mechanisms of action.

Acrivastine, terfenadine and diphenhydramine effects on driving performance as a function of dose and time after dosing

The study was conducted according to a nine-way, observer- and subject-blind, cross-over design. Its purpose was to compare the single-dose effects of the following drugs on driving performance: acrivastine (8, 16 and 24 mg); the combination of acrivastine (8 mg) with pseudoephedrine (60 mg); terfenadine (60, 120 and 180 mg); diphenhydramine-HCl (50 mg); and placebo. The subjects were 18 healthy female volunteers. Drug effects were assessed in two repetitions of two driving tests (highway driving and car-following) after each treatment. Acrivastine's impairing effects in both driving tests were similarly dose-related. The 8-mg dose had a small, but significant, effect on highway driving in the first trial. The 16-mg and 24-mg doses significantly impaired driving in both tests during the first trial and the 24-mg dose did so again during the second trial. Neither the combination of acrivastine with pseudoephedrine nor terfenadine caused any significant impairment of performance. Diphenhydramine significantly impaired driving in both tests during every trial. In conclusion, the normal therapeutic dose of acrivastine (8 mg) had little effect on driving performance, and virtually none when that dose was given in combination with pseudoephedrine (60 mg). Higher doses of acrivastine severely impaired driving performance. Terfenadine had no significant effect on driving performance after any dose while diphenhydramine strongly impaired every important driving parameter.

Efficacy of acrivastine in the treatment of allergic rhinitis during natural pollen exposure: onset of action

In a placebo-controlled, randomized, and double-blind 1-day field study, the efficacy and onset of action of capsule acrivastine 8 mg were evaluated in 42 patients suffering from allergic rhinoconjunctivitis elicited by natural grass pollen exposure. Before and for 2 h after treatment, the patients scored the severity of five rhinoconjunctivitis symptoms every 10 min on a 0-5 scale (0 = no symptoms; 5 = very severe symptoms). The number of sneezes was recorded, and every 30 min, measurements of nasal peak flow were made. Before treatment, there was no difference in median total symptom score (mTSS) between the acrivastine group (A) and the placebo group (P) (12 and 12, respectively). Time of onset was estimated by an exponential decay model to be 19 min (95% confidence interval 0-39 min). A statistically significant difference in percent reduction of mTSS between A and P was observed for the first time 46 min after treatment start (A = 22%, P = 0%, P < 0.05). A 50% reduction in total symptom score (TSS) was achieved within 60 min by 38% in A and 17% in P (NS), and within 80 min in 52% and 17%, respectively (P < 0.05). The median time for 50% reduction in TSS (MT50) was 80 min for A and > 120 min for P (P < 0.01). The symptom score of sneezing and number of sneezes were evaluated for periods of 30 min. The difference between A and P became statistically significant from 31-60 and 61-90 min, respectively (P < 0.05 and P < 0.01). Objective and subjective determinants in the different time intervals were well correlated. Improvement of nasal congestion was observed in A at 91-120 min, as measured by nasal peak flow.

Effects of acrivastine and terfenadine on skin reactivity to histamine

The response to the histamine hydrochloride prick skin test was studied in 24 healthy volunteers who received, in random order and at least four days apart, acrivastine (8 mg), terfenadine (120 mg), and placebo. The tests were performed on either side of the back before and at the time of administration (single dose), then every 30 minutes for two hours, and every hour for the following four hours. Evaluation was based on the mean of two measurements of the surface area of the wheal-and-flare reaction accompanied by assessment of topical pruritus. The response to histamine was decreased markedly in the two active treatment groups. Although within one hour of injection, the activity of both antihistamines was consistently greater than that of placebo, the kinetics of action of the two products nevertheless differed; indeed acrivastine was active against flare and wheal earlier (within 30 minutes); terfenadine proved to be more active than acrivastine only on flare and only at the later times (four, five, and six hours). The safety study primarily demonstrated drowsiness in one-fourth of the patients receiving placebo and active treatment.

A phase II study of vinblastine in combination with acrivastine in patients with advanced renal cell carcinoma

Renal cell carcinoma exhibits chemoresistance attributable in part to the P-glycoprotein drug efflux mechanism. Acrivastine is a hydrophylic antihistamine that has been shown in vitro to reverse this form of resistance. After five patients were treated on a dose-finding study, seventeen patients with metastatic or unresectable renal cell carcinoma were entered into a phase II study of vinblastine in combination with acrivastine. Patients received oral acrivastine at doses of 400 mg every 4 hours for 6 days and a 96-hour continuous infusion of vinblastine at a dose of 1.6 mg/m2/24 h. Of 15 evaluable patients, no tumor responses were seen. The regimen was well-tolerated with the majority of toxicities being gastrointestinal and hematologic. Serum levels of acrivastine, its principal metabolite (270C81) and vinblastine were measured during the study. Based on in vitro data, the plasma levels of acrivastine were within a range adequate to block P-glycoprotein activity. High doses of acrivastine were well-tolerated clinically, however, the combination of acrivastine and vinblastine was not active against renal cell carcinoma.

Time of onset of action of acrivastine in the skin of pollen-allergic subjects. A double-blind, randomized, placebo-controlled comparative study

The purpose of this study was to assess the time of onset of action of acrivastine in suppressing the wheal response to histamine (10 mg/ml) and allergen (10,000 and 100,000 BU/ml) in the skin prick test. Ten subjects with a well-documented allergy to pollen received single doses of 8 mg of acrivastine and placebo according to a randomized, double-blind, placebo-controlled, crossover treatment design. Duplicate skin prick tests were performed 0, 15, 20, 25, 30, and 60 min after medication. The results demonstrated a statistically significant suppression of the wheal reactions 15-20 min after medication, depending on the reaction producers used. The sum of all three producers showed a statistically significant effect on the wheal reaction 15 min after medication. The upper 95% confidence limit for time lag from dosing of acrivastine until reduction from placebo level commences was 6.5 min. The study substantiates that orally administered acrivastine has a rapid onset of action in the skin of allergic subjects. The results indicate that allergen SPT is a more sensitive tool for studying antihistaminergic activity than histamine SPT.

Initiation of the effects of acrivastine and cetirizine on histamine-induced wheals and itch in human skin

The initiation of the antihistamine effect of a single dose of acrivastine (8 mg) or cetirizine (10 mg) on wheals and itch induced by histamine dihydrochloride (10 mg/ml) in the prick test was studied in a randomized cross-over design employing 20 healthy medical students. The prick test was performed before ingestion of the drug and after 15, 20, 25, 30, 60 and 90 min and 2, 3 and 4 h. Local symptoms (itching) were recorded on a visual analogue scale. The inhibitory effect of acrivastine on the histamine wheal was first noticed 20 min (p < 0.01) after ingestion of the drug and that of cetirizine after 60 min (p < 0.001). The maximum effect of cetirizine, at 4 h, was greater than that of acrivastine, at 3 h (p < 0.001). The suppression of itching was first noticed 25 min after ingestion with both drugs.

Terfenadine alters action potentials in isolated canine Purkinje fibers more than acrivastine

Acrivastine and terfenadine are second-generation antihistamines with similar pharmacologic profiles and comparable clinical efficacies for allergic rhinitis. However, terfenadine therapy has been associated with cardiovascular side effects that include prolonged QT interval, torsades de pointes, and ventricular fibrillation (VF). We examined the adverse effects induced by terfenadine on evoked action potentials (APs) in isolated canine cardiac Purkinje fibers and determined whether acrivastine causes similar disturbances in this preparation. Terfenadine produced a statistically significant decrease in the maximal rate of increase in the AP (dV/dt) at 10(-7) M, which corresponds to the highest plasma concentration observed clinically. The IC50 (mean +/- SEM) value for terfenadine-induced inhibition of dV/dt was 1.3 +/- 0.3 x 10(-6) M. The decrease in dV/dt caused by terfenadine became more pronounced with faster rates of stimulation. Acrivastine at a concentration of 10(-5) M, a value 10 times higher than plasma concentrations observed in clinical studies, caused no significant changes in AP duration (APD) or dV/dt. The IC50 (mean +/- SEM) value for the acrivastine-induced inhibition of dV/dt was estimated to be 8.0 +/- 3.7 x 10(-3) M. Terfenadine blocked the evoked AP at 3 x 10(-6) M, whereas no block was observed with acrivastine at 10(-3) M. The effective serum concentration of acrivastine is approximately 100 times higher than that of terfenadine. Because the IC50 value for inhibition of dV/dt for acrivastine is approximately 6,000 times greater than that for terfenadine, we estimate that acrivastine is approximately 60-fold less likely to cause disturbances in cardiac conduction than terfenadine.

The new H1 antihistamines. Treatment of urticaria and other clinical problems

The new H1 antihistamines are a major therapeutic advancement in the treatment of allergic disorders such as urticaria and allergic rhinitis. Their efficacy combined with greatly reduced sedating and anticholinergic side effects makes the new class of H1 antihistamines the first-line treatment in the management of urticaria and mild angioedema. The choice of a particular low-sedating H1 antihistamine depends on pharmacokinetic considerations, the severity of the problem (systemic steroids and epinephrine are the first-line treatment for severe angioedema), and the requirement for limiting the frequency of administration. The efficacy of the new H1 antihistamines in the treatment of itch due to atopic eczema and systemic disease remains uncertain, and further controlled clinical trials are needed to elucidate their possible role in these conditions.

Disposition of acrivastine in the male beagle dog

Three male beagle dogs were given 10 mg/kg iv and oral doses of [14C]acrivastine, a novel nonsedating antihistaminic agent, in a nonrandomized crossover experiment. Urine and feces were collected for 72 hr after dosing. After iv dosing, a mean of 34% was recovered in the urine, and 63% was recovered in the feces. After po dosing, a mean of 29% of the radiocarbon was recovered in the urine, and 63% was recovered in the feces (dose adjusted for 14% lost in vomitus). Acrivastine and three major metabolites were detected in the excreta. The metabolites were identified as a side-chain-reduced analog of acrivastine (metabolite 3, 270C81), a gamma-aminobutyric acid analog of 270C81 (metabolite 2), and a benzoic acid analog of 270C81 (metabolite 1). After iv dosing, 34% of the dose was excreted as parent drug, 21% as metabolite 3, 15% as metabolite 2, and 6% as metabolite 1, while after po dosing, 35% of the dose was excreted as parent drug, 18% as metabolite 3, 11% as metabolite 2, and 7% as metabolite 1. Pharmacokinetic analysis of acrivastine plasma concentration-time curves after both routes of administration indicated a mean total body clearance of 17.3 ml/min/kg, a Vss of 0.93 liter/kg, a terminal half-life of 0.7 hr, and an oral bioavailability of 40%. The apparent plasma half-life of the metabolite, 270C81, was 1.5 hr. Analysis of AUC values indicated that greater amounts of 270C81 than acrivastine circulated in plasma after both iv and po dosing, and that first-pass metabolism of acrivastine to 270C81 occurred. The results indicated that acrivastine was extensively metabolized in the dog to 270C81 and suggested that 270C81 itself underwent further metabolism to metabolites 1 and 2.

Acrivastine. A review of its pharmacological properties and therapeutic efficacy in allergic rhinitis, urticaria and related disorders

Acrivastine is a short acting histamine H1-receptor antagonist with a rapid onset of action. Double-blind clinical trials have shown acrivastine (usually 8mg three times daily) to be an effective and well tolerated antihistamine in the treatment of chronic urticaria and allergic rhinitis. Acrivastine was more effective than placebo and similar in efficacy to clemastine or terfenadine in the treatment of seasonal allergic rhinitis. In the treatment of dermatoses in which histamine has a pathogenetic role, the efficacy of acrivastine was superior to that of placebo and similar to that of usual dosages of clemastine, hydroxyzine, chlorpheniramine, cyproheptadine or terfenadine. Acrivastine caused less drowsiness than clemastine, the incidence of adverse effects being indistinguishable from that with placebo or terfenadine. Thus, acrivastine is an effective addition to drugs currently available for the treatment of patients with allergic diseases in whom a histamine H1-receptor antagonist is indicated. Because of its rapid onset of action acrivastine will be particularly useful for 'on demand' therapy in patients with intermittent symptoms.

A cross-over comparison of acrivastine, pseudoephedrine and their combination in seasonal allergic rhinitis

In a four period, double-blind cross-over study, forty patients with moderate to severe symptoms of seasonal allergic rhinitis received in randomised order 8 mg acrivastine, 60 mg pseudoephedrine, 8 mg acrivastine plus 60 mg pseudoephedrine and placebo. Each treatment was given three times daily for six days with a one day washout period between treatments. Acrivastine alone significantly reduced all the symptom severity scores when compared to placebo or pseudoephedrine alone (p less than 0.01). These severity scores were assigned daily by patients for itchy nose/throat, sneezing, running nose, blocked nose, watery eyes, itchy eyes and overall symptoms. The combination of acrivastine and pseudoephedrine was significantly better than either placebo or pseudoephedrine alone in controlling all symptom scores (p less than 0.01) and it was also superior to acrivastine alone (p less than 0.05) in controlling all symptoms except itchy eyes. The results confirm the expected additive rather than synergistic effect of acrivastine and pseudoephedrine in combination. The control of symptoms assessed at the end of each treatment period was considered either excellent or good by 79% of patients and 84% of investigators for acrivastine plus pseudoephedrine and, for acrivastine alone, by 69% of patients and 67% of investigators. Both acrivastine alone and acrivastine and pseudoephedrine in combination were well tolerated. There was no significant difference in the number of adverse experiences reported in either of these two groups compared to the number of adverse experiences reported in the placebo group.

Application of HPLC-thermospray ionization mass spectrometry for the analysis of triprolidine and its metabolite hydroxymethyltriprolidine in biological samples

High-performance liquid chromatography coupled to positive ion mode thermospray ionization mass spectrometry has been used to characterize triprolidine and its known metabolite hydroxymethyltriprolidine. The method allows direct analysis of these compounds in complex biological matrices. Analysis of an extract from a microbial biotransformation experiment with triprolidine was performed and the results included two baseline-resolved chromatographic peaks. The [M + H]+ ion obtained from the mass spectrum of the first peak was consistent with that of hydroxymethyltriprolidine, and the mass spectrum of the second peak corresponded to triprolidine. Under the described conditions, the minimum detectable level of triprolidine without filament enhancement was estimated at about 10 micrograms injected on column.

Pharmacokinetics of acrivastine after oral and colonic administration

Six healthy male volunteers participated in this randomized, crossover open-label pharmacokinetic study consisting of two dosing segments separated by a washout period of at least 5 days. During each dosing segment, each volunteer received 12 mg of acrivastine, an investigational histamine H1-receptor antagonist, in a syrup form either orally or by colonic administration in random order. After oral and colonic administration, respectively, the following mean +/- SD pharmacokinetic parameters were obtained: Cmax 179 +/- 11 and 13.8 +/- 5.2 ng/ml; tmax, 0.85 +/- 0.13 and 3.60 +/- 0.56 hr; AUC0-12 hr, 576 +/- 57 and 104 +/- 46 hr.ng/ml. Differences between the oral and colonic administration for all three parameters were statistically significant (P less than 0.001). The mean +/- SD relative bioavailability of acrivastine from colonic compared to oral dosing was 0.18 +/- 0.09. It may be concluded, therefore, that appreciable absorption of acrivastine from the colon does not take place. These results suggest that comparison of pharmacokinetic profiles of some drugs after oral and colonic administration may be a useful technique for predicting bioavailability from a sustained release oral formulation.

Acrivastine in two doses compared with placebo in a multicentre, parallel group study for the treatment of seasonal allergic rhinitis

In a placebo controlled, randomised, multicentre study the efficacy and safety of multiple doses of acrivastine, a derivative of the antihistamine tripolidine (Actidil) were evaluated in patients exhibiting symptoms of seasonal allergic rhinitis. Over the 10 day treatment period, 103 patients received, twice daily, either 4 mg and 8 mg of acrivastine or a placebo. Three patients withdrew from the study due to poor symptom control and two due to adverse experiences. The reporting of adverse experiences was evenly distributed between the treatment and placebo periods. Acrivastine did not affect the haematological, biochemical or urinalysis screens. Both 4 mg and 8 mg acrivastine alleviated the symptoms of seasonal allergic rhinitis with significant improvements in the symptom scores for sneezing, running nose and the calculated overall score. In addition, 8 mg acrivastine reduced the symptom scores for watery eyes and itchy throat. Acrivastine was both well tolerated and effective in the treatment of seasonal allergic rhinitis.

Acrivastine in seasonal allergic rhinitis: two randomized crossover studies to evaluate efficacy and safety

In two randomized crossover studies, the antihistamine, acrivastine, was evaluated for the treatment of seasonal allergic rhinitis. One study on 31 patients found both 4 and 8 mg acrivastine given three times daily to be significantly better than placebo for alleviating hay fever. There were no significant differences in symptom scores between the two doses, although more patients (63%) favoured 8 mg acrivastine over the 4 mg dose (46%) or placebo (35%). The other study found the higher dosage regimen to be similar in efficacy to 1 mg clemastine given three times daily. Both dosages were significantly better than placebo for reducing symptom scores in all 18 evaluable patients. The incidence of adverse experiences was low in both studies; there being no dose-related effects of acrivastine. In the second study, drowsiness, probably or possibly treatment related, occurred on seven occasions during clemastine treatment and once with acrivastine. These studies indicate that 8 mg acrivastine given three times daily is both well tolerated and of equal efficacy to clemastine for the treatment of seasonal allergic rhinitis.