by Karl Harrison

Long-Acting Antihistamine/Extended Release Decongestant

Loratadine is a white to off-white powder, not soluble in water, but very soluble in organic solvents. Loratadine has the chemical name, ethyl 4- (8-chloro-5,6- dihydro-11 H-benzo [5,6] cyclohepta [1,2-b] pyridin-11-ylidene) -1- piperidine carboxylate.

Loratadine is a long-acting tricyclic antihistamine with selective peripheral histamine H1-receptor antagonistic activity. Human histamine skin wheal studies following single and repeated oral doses of loratadine have shown that the drug exhibits an antihistaminic effect beginning within 1 to 3 hours, reaching a maximum at 8 to 12 hours and lasting in excess of 24 hours.There was no evidence of tolerance to this effect developing after 28 days of dosing with loratadine.

Pharmacokinetic studies following showed that loratadine is rapidly absorbed and extensively metabolized to an active metabolite (descarboethoxyloratadine)

References RxList - The Internet Drug Index