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 in the ICU.
Cisatracurium Besylate is a nondepolarizing skeletal muscle relaxant for intravenous administration. Cisatracurium Besylate acts on cholinergic receptors, blocking neuromuscular transmission. This action is antagonized by acetylcholinesterase inhibitors such as neostigmine. The neuromuscular block produced by cisatracurium besylate is readily antagonized by anticholinesterase agents once recovery has started. As with other nondepolarizing neuromuscular blocking agents, the more profound the neuromuscular block at the time of reversal, the longer the time required for recovery of neuromuscular function. Compared to other neuromuscular blocking agents, it is intermediate in its onset and duration of action.
mechanism of action
Cisatracurium Besylate binds to the nicotinic acetycholine (cholinergic) receptors in the motor endplate and blocks access to the receptors. In the process of binding, the receptor is actually activated - causing a process known as depolarization. Since it is not degraded in the neuromuscular junction, the depolarized membrane remains depolarized and unresponsive to any other impulse, causing muscle paralysis.
Overdosage with neuromuscular blocking agents may result in neuromuscular block beyond the time needed for surgery and anesthesia.
The degradation of cisatracurium is largely independent of liver metabolism. Results from in vitro experiments suggest that cisatracurium undergoes Hofmann elimination (a pH and temperature-dependent chemical process) to form laudanosine and the monoquaternary acrylate metabolite. The monoquaternary acrylate undergoes hydrolysis by non-specific plasma esterases to form the monoquaternary alcohol metabolite. The monoquaternary alcohol metabolite can also undergo Hofmann elimination but at a much slower rate than cisatracurium. Laudanosine is further metabolized to desmethyl metabolites which are conjugated with glucuronic acid and excreted in the urine.
Elimination half-life of 22 minutes.
route of elimination
Biliary and urinary excretion were the major routes of excretion of radioactivity (totaling >90% of the labeled dose within 7 hours of dosing), of which atracurium represented only a minor fraction.