Esmolol (trade name Brevibloc) is a cardioselective beta1 receptor blocker with rapid onset, a very short duration of action, and no significant intrinsic sympathomimetic or membrane stabilising activity at therapeutic dosages.
Esmolol is rapidly hydrolyzed by plasma esterases and not by plasma cholinesterases. Esmolol's short duration of action is based on the ester-methyl side chain which allows for quick hydrolysis. Esmolol's structure is reflected in its name, es-molol as in ester-methyl. Plasma cholinesterases and red cell membrane acetylcholinesterase do not have any action. This metabolism results in the formation of a free acid and methanol. The amount of methanol produced is similar to endogenous methanol production. Its elimination half-life is about 9 minutes.