Pancuronium blood level monitoring in patients with tetanus

Overdosage of muscle relaxant has been given as a possible explanation for the hypotensive episodes occurring during the management of tetanus. The aim of the present work was to study the pharmacokinetics of pancuronium during long term infusion. Pancuronium was administered to eight patients with severe tetanus for a period varying from 8 to 24 days. The concentration of pancuronium was measured daily in plasma and urine using a fluorimetric method. The plasma concentration varied from 0.27 to 0.48 microgram/ml. No tendency to accumulation was observed. The plasma concentration fell rapidly below the level associated with muscle relaxation when pancuronium was discontinued. This absence of accumulation can be explained by a rapid elimination of pancuronium through the kidney according to a process of ultrafiltration.