pancuronium and Atrophy

Topics: Atrophy; Drug Resistance; Female; Humans; Intensive Care Units; Pancuronium

To determine whether disuse atrophy of skeletal muscle results in resistance to pancuronium, the dose response to pancuronium was determined simultaneously in both gastrocnemius muscles of six dogs that had one hind limb immobilized in a plaster cast for one month. Muscle responses were evoked during pentobarbital-nitrous oxide anesthesia by stimulation of the exposed sciatic nerves, using the train-of-four pattern. Muscle subject to disuse atrophy was resistant to pancuronium. The ED50 (dose of pancuronium which causes a 50 per cent depression of twitch tension) was 0.051 mg/kg for casted and 0.027 mg/kg for uncasted limbs for a potency ratio of 1.89. On the basis of these data the author predicts that bedridden or immobilized patients are likely to require greater doses of nondepolarizing relaxants for paralysis.

Topics: Animals; Atrophy; Dogs; Dose-Response Relationship, Drug; Drug Resistance; Immobilization; Muscles; Pancuronium; Paralysis