Loratadine
Loratadine is a drug used to treat allergies. It is marketed by Schering-Plough under several trade names such as Claritin®, Clarityn® or Claratyne® depending on the market. Its active metabolite, desloratadine, is also on the market.
Loratadine
|
| Ethyl 4-(8-chloro-5,6-dihydro-11H- benzo[5,6]cyclohepta[1,2-b]pyridin-11-ylidine)- 1-piperidinecarboxylate
|
| Molecular Weight
| 382.89
|
| Empiric Formula
| C22H23ClN2O2
|
| ATC code
| R06AX13
|
| Metabolism
| hepatic
|
| Pregnancy category
| B (USA)
B1 (Aus)
|
Available forms
Loratadine is available as tablets and oral suspension.
Mechanism of action
Loratadine 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.
Pharmacokinetics
Loratadine is rapidly absorbed from the gastro-intestinal tract and it has rapid first-pass hepatic metabolism. Loratadine is almost totally bound to plasma proteins. Its metabolite, desloratadine (descarboethoxyloratadine), is also active, but binds to plasma proteins only moderately. The half-life of loratadine is on average 8 hours, and its metabolite's 28 hours. About 40% is excreted as conjugated metabolites into the urine and similar amount into the feces. Traces of unmetabolised loratadine can be found in the urine.
Side effects
Most common side-effects are fatigue, drowsiness, dry mouth, headache, and gastrointestinal disturbances.
