Article: Desloratadine

Desloratadine
Systematic (IUPAC) name
8-chloro-6,11-dihydro-11-(4-piperdinylidene)- 5H-benzo[5,6]cyclohepta[1,2-b]pyridine
Identifiers
CAS number	100643-71-8
ATC code	R06AX27
PubChem	124087
DrugBank	APRD00324
Chemical data
Formula	C19H19ClN2
Mol. weight	310.82
Pharmacokinetic data
Bioavailability	rapidly absorbed
Protein binding	85%
Metabolism	Liver
Half life	50 hours
Excretion	40% as conjugated metabolites into urine similar amount into the feces
Therapeutic considerations
Pregnancy cat.	B1(AU) C(US)
Legal status	POM(UK)
Routes	oral

Desloratadine is a drug used to treat allergies. It is marketed under several trade names such as NeoClarityn®, Claramax®, Clarinex® and Aerius®. It is an active metabolite of loratadine, which is also on the market.

Available forms

Desloratadine is available as tablets and oral suspension.

Mechanism of action

Desloratadine is a tricyclic antihistamine, which has a selective and peripheral H₁-antagonist action. It has a long-lasting effect and does not cause drowsiness because it does not readily enter the central nervous system.^[1]

Side effects

Most common side-effects are fatigue, drowsiness, dry mouth, headache, and gastrointestinal disturbances.

Desloratadine vs. loratadine

Desloratidine is the major metabolite of loratadine. There are no head to head randomised controlled trials of the two preparations which are expected to be therapeutically closely equivalent in those with normal drug metabolism. A survey of patients dissatisfied with loratadine reported equal or better satisfaction with desloratadine as fexofenadine.^[2] This study for reasons known only to its authors did not report on how many patients who took loratadine were satisfied with it which it could easily have done. The paper refers to 61 patients making the transition from loratadine to desloratidine and up to 10,023 may have been taking loratadine ! There is some evidence that fexofenadine and loratadine have effectively identical clinical profiles.

A November 2003 article published in the journal American Family Physician about the safety, tolerability, effectiveness, price, and simplicity of desloratadine concluded the following:^[3]

"Desloratadine is similar in effectiveness to fexofenadine and would be expected to produce results similar to loratadine and other nonsedating antihistamines. There is no clinical advantage to switching a patient from loratadine to desloratadine. However, it may be an option for patients whose medical insurance no longer covers loratadine if the co-pay is less than the cost of the over-the-counter product."