Atracurium
Click for larger image
Used as an adjunct
to general anesthesia to facilitate endotracheal intubation and to
provide skeletal muscle relaxation during surgery or mechanical ventilation.
Atracurium is one of several intermediate-acting nondepolarizing NeuroMuscular Blocking Drugs (NMBDs).
Nondepolarizing intermediate-acting NMBDs function by competing with
Acetylcholine in binding to postjunctional nicotinic cholinergic receptors
on the motor end plate and prevent changes in ion permeability. Ion
permeability is responsible for propagation of action potentials in
neurons and is important in cell function as well. Thus atracurium
and other non-depolarizing NMBDs prevent depolarization of "message"
receptors and effectively prevents the propagation of the message
to the muscles. This causes temporary skeletal muscle paralysis. Atracurium
begins acting approximately 3 to 5 minutes after administration and
has a duration of about 20 to 35 minutes at an effective dose (ED)
of approximately 0.2 mg/kg which is effective for ~95% of patients
(ED95). Possible side effects of the drug may include heart rate irregularities
and/or a decrease in blood pressure at relatively large doses.
The benefit of Atracurium over other NMBDs is that it has two routes
of metabolism (how the body deals with the drug). Significantly, however,
these routes are independent of liver and kidney function as well
as blood plasma cholinesterase activity. Thus, the effectiveness of
Atracurium is similar in normal patients and those with hepatic problems,
kidney dysfunction, or atypical plasma cholinesterase. For this reason,
atracurium may be preferentially selected for use with persons with
renal or hepatic medical histories.
