Interaction between famotidine and neuromuscular blockers: an in vivo study in rats

The effect of histamine 2-antagonist famotidine on neuromuscular paralysis induced with either nondepolarizing or depolarizing neuromuscular blocking drugs was examined in anesthetized and mechanically ventilated rats. Neuromuscular paralysis, as judged by tibialis anterior muscle twitch tension in response to sciatic nerve stimulation, was maintained at about 50% with intravenous bolus and infusion regimens of either atracurium, gallamine, succinylcholine, or decamethonium. Famotidine, 0.1, 1, and 4 mg/kg, intravenously, were then administered at 5-min intervals as the infusion of the neuromuscular blocker was continued. Famotidine at any of these three doses failed to alter the steady state neuromuscular paralysis produced with either atracurium (prefamotidine versus final postfamotidine paralysis (mean +/- SE depression of twitch tension, n = 6, 49.8 +/- 2.8 vs 51.5 +/- 2.6%), gallamine (47.8 +/- 1.6 vs 47.6 +/- 3.0%), succinylcholine (49.2 +/- 1.8 vs 49.4 +/- 2.0%), or decamethonium (50.3 +/- 2.1 vs 51.5 +/- 2.0%). Intravenous famotidine at human therapeutic doses, fails to alter neuromuscular function in vivo in rats.