Tripitramine
Tripitramine, or tripitamine, is an antimuscarinic drug which was never marketed.
Pharmacology
The drug is a selective antagonist of the muscarinic [acetylcholine receptor|muscarinic acetylcholine] M2 receptor. Its affinities for the muscarinic acetylcholine receptors are 0.27nM for the M2 receptor, 1.58nM for the M1 receptor, 6.41nM for the M4 receptor, 33.87nM for the M5 receptor, and 38.25nM for the M3 receptor. Tripitramine has been found to be cardioselective and to increase heart rate in animals.
Chemistry
Structurally, it consists of three pirenzepine- or AQ-RA 741-like tricyclic moieties bound together by a long amine-containing hydrocarbon chain similar to the one found within methoctramine. Related compounds with analogous structural designs include dipitramine, spirotramine, caproctamine, and benextramine, among others.
History
Tripitramine was first described in the scientific literature by 1993. It was developed in efforts to discover more highly selective M2 receptor antagonists than methoctramine.