CLARINEX-D 12 HOUR Extended Release Tablets (desloratadine/pseudoephedrine sulfate)(七)
ate NF, corn starch NF, edetate disodium USP, citric acid anhydrous USP, stearic acid NF and FD&C Blue No. 2 aluminum lake dye.
Desloratadine, 1 of the 2 active ingredients of CLARINEX-D 12 HOUR Extended Release Tablets, is a white to off-white powder that is slightly soluble in water, but very soluble in ethanol and propylene glycol. It has an empirical formula: C19H19ClN2 and a molecular weight of 310.8. The chemical name is 8-chloro-6,11-dihydro-11-(4-piperdinylidene)-5H-benzo[5,6] cyclohepta [1,2-b]pyridine and has the following structure:
Chemical Structure
Pseudoephedrine sulfate, the other active ingredient of CLARINEX-D 12 HOUR Extended Release Tablets, is the synthetic salt of one of the naturally occurring dextrorotatory diastereomers of ephedrine and is classified as an indirect sympathomimetic amine. Pseudoephedrine sulfate is a colorless hygroscopic crystal or white, hygroscopic crystalline powder, practically odorless, with a bitter taste. It is very soluble in water, freely soluble in alcohol, and sparingly soluble in ether. The empirical formula for pseudoephedrine sulfate is (C10H15NO)2 • H2SO4; the chemical name is benzenemethanol, α-[1-(methylamino) ethyl]-,[S-(R*,R*)]-, sulfate (2:1)(salt); and the chemical structure is:
Chemical Structure
12 CLINICAL PHARMACOLOGY
12.1 Mechanism of Action
Desloratadine is a long acting tricyclic histamine antagonist with selective H1-receptor histamine antagonist activity. Receptor binding data indicate that at a concentration of 2 to 3 ng/mL (7 nanomolar), desloratadine shows significant interaction with the human histamine H1 receptor. Desloratadine inhibited histamine release from human mast cells in vitro. Results of a radiolabeled tissue distribution study in rats and a radioligand H1-receptor-binding study in guinea pigs showed that desloratadine does not readily cross the blood brain barrier. The clinical significance of this finding is unknown.
Pseudoephedrine sulfate is an orally active sympathomimetic amine and exerts a decongestant action on the nasal mucosa. Pseudoephedrine sulfate is recognized as an effective agent for the relief of nasal congestion due to allergic rhinitis. Pseudoephedrine produces peripheral effects similar to those of ephedrine and central effects similar to, but less intense than, amphetamines. It has the potential for excitatory side effects.
12.2 Pharmacodynamics
Wheal and Flare: Human histamine skin wheal studies following single and repeated 5 mg doses of desloratadine have shown that the drug exhibits an antihistaminic effect by 1 hour; this activity may persist for as long as 24 hours. There was no evidence of histamine-induced skin wheal tachyphylaxis within the desloratadine 5mg group over the 28 day treatment period. The clinical relevance of histamine wheal skin testing is unknown.
Effects on QTc: In clinical trials for CLARINEX-D 12 HOUR Extended Release Tablets, ECGs were recorded at baseline and endpoint within 1 to 3 hours after the last dose. The majority of ECGs were normal at both baseline and endpoint. No clinically meaningful changes were observed following treatment with CLARINEX-D 12 HOUR Extended Release Tablets for any ECG parameter, including the QTc interval. An increase in the ventricular rate of 7.1 and 6.4 bpm was observed in the CLARINEX-D 12 HOUR Extended Release Tablets and pseudoephedrine groups, respectively, compared to an increase of 3.2 bpm in subjects receiving desloratadine al |
