Clarinex
Desloratadine: A preclinical and clinical overview.

Norman P, Dihlmann A, Rabasseda X.

Norman Consulting, Burnham, England. xrabasseda prous.com

A new competitive histamine H(1)-receptor antagonist with superior binding affinity at this receptor as compared with other common antihistamines, desloratadine is the active metabolite of loratadine, the most extensively used agent of this class. Under development for the treatment of allergic rhinitis and urticaria and currently awaiting regulatory approval in the United States, desloratadine was recently approved and became commercially available in Europe for the treatment of allergic disease. Desloratadine is at least 50-fold more potent in vitro and appears to be 10-fold more potent in vivo than loratadine. The new antihistamine is metabolized to 3-hydroxydesloratadine, which retains biological activity. Absorption of orally administered desloratadine is dose proportional, and desloratadine achieves steady-state concentrations after approximately 5 doses with once-daily administration. This is consistent with mean half-life values of 24-27 h and a 24-h dosing interval. The absorption of desloratadine is not affected by food and there are no clinically relevant drug-drug interactions. In randomized, double-blind, placebo-controlled clinical trials, a single 5 mg dose of desloratadine conferred significant relief of seasonal allergic rhinitis (SAR) symptoms - including the complaint of nasal congestion - within hours of the first dose, and these effects were sustained both for the entire 24-h dosing interval and up to 2-4 weeks with once-daily treatment (5 mg/day). In addition, patients with seasonal exacerbations of mild to moderate asthma derived similar clinical benefits from desloratadine, with significant, first-dose relief of both SAR-related complaints such as nasal congestion as well as asthma symptoms. In addition, beta(2) agonist requirements for symptom management were significantly reduced from baseline in these asthma patients when treated with the 5 mg/day desloratadine regimen as compared with placebo. Also experiencing marked relief of symptoms upon treatment with desloratadine were patients with chronic idiopathic urticaria, who exhibited significant first-dose relief of pruritus and sustained reductions in this symptom, numbers of lesions (and size of largest hive) and sleep disturbances, with a marked improvement in their ability to carry out activities of daily living. The clinical benefits of desloratadine in the above clinical settings were accompanied by general improvements in quality of life. Desloratadine does not cross the blood-brain barrier, as demonstrated by both human studies using cognitive indices as well as work in animal models. Desloratadine is well tolerated, and no significant drug-related (or food-related) adverse effects were noted when the agent was administered together with cytochrome P450 inhibitors (e.g., ketoconazole, erythromycin). Administration of desloratadine has not been shown to cause any significant changes in cardiac activity at therapeutic doses, even at 9-fold higher doses, or in the presence of P450 inhibitors. Nor does administration of desloratadine lead to sedation, even in the presence of alcohol. (c) 2001 Prous Science. All rights reserved.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=12768222&dopt=Abstract desloratadine Clarinex



Clarinex
Assessing satisfaction with desloratadine and fexofenadine in allergy patients who report dissatisfaction with loratadine.

Glass DJ, Harper AS.

Zynx Life Sciences, Cerner Corporation, Beverly Hills, CA, USA. dglass cerner.com

BACKGROUND: The FDA recently moved loratadine (Claritin) from prescription only status to over-the-counter (OTC). In response to the availability of an OTC non-sedating antihistamine, many managed care organizations are reevaluating which if any prescription antihistamines should remain on formulary. From a managed care perspective, determining which of the remaining prescription antihistamines results in the greatest patient satisfaction with allergy treatment would be informative. METHODS: We report on a weighted cross sectional survey (n = 10,023) delivered online to a sample of allergy sufferers in the U.S. during the month of December 2002. Two segments were identified for analysis: patient who were dissatisfied with loratadine and converted to desloratadine (Clarinex; n = 61), and patients who were dissatisfied with loratadine and converted to fexofenadine (Allegra; n = 211). The two segments were compared along a series of measures that the literature suggests are related to treatment satisfaction. RESULTS: The survey found that two of the satisfaction measures differentiated desloratadine converters from fexofenadine converters (p <.05): mean sum of self-reported adverse events and nighttime awakening due to allergy symptoms. For the remainder of satisfaction measures though, patients who were dissatisfied with loratadine reported equal duration of coverage and satisfaction with desloratadine as fexofenadine. When severity of disease was controlled for in the analysis, a pattern emerged suggesting greater levels of satisfaction amongst loratadine dissatisfied patients who converted to desloratadine. Point estimates suggest a consistent pattern favoring desloratadine patient satisfaction, with statistically significant results reported for sum of adverse effects, nighttime awakening due to symptoms, symptom severity just prior to the next dose, and overall satisfaction (p < 0.05). CONCLUSIONS: On average, patients who were dissatisfied with loratadine reported equal or better satisfaction with desloratadine as fexofenadine. Patients with severe allergic rhinitis reported greater satisfaction when converted from loratadine to desloratadine than fexofenadine for select satisfaction measures. These results suggest that if managed care intends to position prescription antihistamines as second line for OTC loratadine treatment dissatisfaction, desloratadine is a useful treatment alternative. These findings, while informative to formulary decision-makers, must be interpreted with caution. Only through head-to-head controlled clinical trials can differences in efficacy and safety be established.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=12917016&dopt=Abstract desloratadine Clarinex



Clarinex
High-performance liquid chromatographic method for the bioequivalence evaluation of desloratadine fumarate tablets in dogs.

Liu L, Qi M, Wang P, Li H.

School of Pharmacy, Shenyang Pharmaceutical University, Shenyang, PR China.

A simple HPLC method was developed for the determination of desloratadine in dog plasma and was used for evaluating the bioequivalence of desloratadine fumarate tablets and desloratadine tablets in dogs. Chromatographic separation was performed on a Hypersil CN column (150 mm x 5.0 mm, 5 microm) using a mixture of methanol, acetonitrile and phosphate buffer (pH 5.5; 0.01 mol/l) (35:35:30, v/v/v) as mobile phase delivered at a flow rate of 0.8 ml/min. The detection was set at 241 nm. The limit of quantitation was 5.0 ng/ml. The calibration range was from 5.0 to 800.0 ng/ml. Inter- and intra-day precision ranged from 1.8 to 3.8% and from 2.2 to 9.0%, respectively. The recovery of desloratadine from dog plasma ranged from 78.8 to 82.0%. The developed method was applied to the bioequivalence studies of desloratadine fumarate tablets (test preparation) and desloratadine tablets (reference preparation) in five dogs. Pharmacokinetic parameters t(max), C(max), AUC(0-t), AUC(0- infinity ), t(1/2) were determined from plasma concentration-time profiles of both preparations. The analysis of variance (ANOVA) did not show any significant difference between the two preparations and 90% confidence intervals fell within the acceptable range for bioequivalence. Based on these statistical inferences it was concluded that the two preparations exhibited comparable pharmacokinetic profiles and that desloratadine fumarate tablets was bioequivalent to desloratadine tablets.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=15019035&dopt=Abstract desloratadine Clarinex



Clarinex
Assessing patient satisfaction with desloratadine after conversion from loratadine, fexofenadine, or cetirizine.

Glass D, Harper A.

Harris Interactive Healthcare Division, New York City, New York 10003, USA. dglass harrisinteractive.com

A number of prescription and nonprescription nonsedating antihistamines are available for the treatment of allergic rhinitis. From a managed care perspective, determining the extent to which a medication conversion to desloratadine from loratadine, fexofenadine, or cetirizine results in maintained or increased patient satisfaction with allergy care would be informative for formulary decision makers and other budget holders. To that end, a survey was undertaken of patient medication assessments after a switch in antihistamines. On average, patients who converted to desloratadine from loratadine, fexofenadine, or cetirizine reported increased satisfaction with desloratadine treatment.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=15038691&dopt=Abstract desloratadine Clarinex