Interaction of vecuronium with piperacillin or cefoxitin evaluated in a prospective, randomized, double-blind clinical trial.

Interactions between beta-lactam antibiotics, particularly acylaminopenicillins, and vecuronium, a widely used muscle relaxant, leading to prolonged neuromuscular blockade have been reported in studies of experimental animals and in a few clinical case reports. In the clinical reports, however, confounding factors always existed. A clinical trial to evaluate interactions between vecuronium and cefoxitin or piperacillin was conducted. Patients having major operations requiring both muscle relaxants as part of general anesthesia and prophylactic antibiotics were entered into the trial and randomly assigned to receive either cefoxitin or piperacillin. The electromyographic twitch response was measured before and after administration of the antibiotic. Five of 27 evaluable patients had minor prolongation of the time to recovery of baseline twitch. No prolonged neuromuscular blockade was observed. There were no differences in responses between the two antibiotic treatment groups. Cefoxitin and piperacillin administered pre- or intra-operatively are not associated with clinically important prolongation of muscle relaxation induced by vecuronium. The potential for prolongation of neuromuscular blockade induced by vecuronium through concomitant administration of piperacillin or cefoxitin as antibiotic prophylaxis was investigated in a clinical trial of 30 patients having major abdominal operations. Quantitative measurement of neuromuscular blockade was done using the electromyographic twitch response to a supramaximal current stimulus.