Pharmacology Of Mivacurium

Indication For inpatients and outpatients, as an adjunct to general anesthesia, to facilitate tracheal intubation and to provide skeletal muscle relaxation during surgery or mechanical ventilation.
Pharmacodynamics Mivacurium is a short-acting, nondepolarizing skeletal neuromuscular blocking agent which is hydrolyzed by plasma cholinesterase. Mivacurium results in a blockade of neuromuscular transmission by binding competitively with cholinergic receptors on the motor end-plate to antagonize the action of acetylcholine. The neuromuscular block produced by mivacurium is readily antagonized by anticholinesterase agents. The deeper the level of neuromuscular block at reversal, the longer the time required for recovery of neuromuscular function and the greater the dose of anticholinesterase agent required. Because spontaneous recovery after mivacurium is rapid, routine reversal may not always result in a clinical benefit.
Mechanism of action Mivacurium binds competitively to cholinergic receptors on the motor end-plate to antagonize the action of acetylcholine, resulting in a block of neuromuscular transmission. This action is antagonized by acetylcholinesterase inhibitors, such as neostigmine.
Absorption Not Available
Volume of distribution Not Available
Protein binding The protein binding of mivacurium has not been determined due to its rapid hydrolysis by plasma cholinesterase.
Metabolism Extensive and rapid via enzymatic hydrolysis catalyzed by plasma cholinesterase. Biotransformation may be significantly slowed in patients with abnormal or decreased plasma cholinesterase activity, especially individuals with a homozygous atypical cholinesterase gene abnormality.
Route of elimination Not Available
Half life The mean elimination half-life ranges from 1.7 to 2.6 minutes in healthy, young adults administered 0.1 to 0.25 mg/kg mivacurium. In 9 patients with end-stage liver disease undergoing liver transplant surgery, plasma clearance was approximately 50% lower than that in 8 control patients with normal hepatic function, while the elimination half-life increased to 4.4 minutes from the 1.8 minute control value.
Clearance Not Available
Toxicity Overdosage with neuromuscular blocking agents may result in neuromuscular block beyond the time needed for surgery and anesthesia.