Name: d-Tubocurarine
Class: Competitive Neuromuscular Blocking Agent
Mech.: Competitive antagonism of ACh on nicotinic receptors at NMJ ® skeletal muscle paralysis.
Absorption: IV
Dist.: Poor CNS.
Metab.: Kidney (up to 1/3 of dose in several hours). Variable liver action.
Excretion, t½: Effect begins in 2 min. 90% of muscle fxn returns in 40-60 min. Residual effect 2-4 hr. Effect terminated by redistribution into other tissues.
Toxicity/S.E.s: Repeated exposure ® cumulative effects, even when spaced 24 hr. apart. Hypotension due to periph. vasodilation as a result of histamine release and symp. ganglia blockade.
Utility: Relaxes skeletal muscle, esp. abdominal wall. Used in surgery.
Special Features: Synergy w/general anesthetics ® lower doses of each necessary. Antag. by IV neostigmine or edrophonium.