OMEPRAZOLE POTENTIATES ATRACURIUM AND SUCCINYLCHOLINE PARALYSIS IN-VIVO IN RATS

We examined the effect of proton pump inhibitor omeprazole on neuromus cular paralysis induced with either nondepolarizing or depolarizing ne uromuscular blocking drugs in anesthetized and mechanically ventilated rats. Neuromuscular paralysis, as judged by tibialis anterior muscle twitch tension in response to sciatic nerve stimulation, was maintaine d at about 50% with intravenous (IV) bolus and infusion regimens of ei ther atracurium or succinylcholine. Omeprazole, 0.5, 1, and 10 mg/kg I V, was then administered at 10-min intervals while the infusion of the neuromuscular blocker was continued. Omeprazole at all three doses in creased the steady-state neuromuscular paralysis produced with either atracurium (preomeprazole versus final postomeprazole paralysis; mean +/- se, n = 6, 53.0% +/- 2.3% vs 80.0% +/- 5.3%) or succinylcholine (5 0.8% +/- 1.5% vs 86.4% +/-:5.1%). Omeprazole, 0.5, 1.0, and 10 mg/kg I V, given directly and without any neuromuscular blocker, produced appr oximately 5% depression of the muscle twitch response. Omeprazole, IV at human therapeutic doses, alters neuromuscular function and enhances the action of both atracurium and succinylcholine in vivo in rats.