We compared the pharmacokinetics and pharmacodynamics of atracurium in eight normal and eight anephric patients during isoflurane anesthesia. Plasma concentrations were measured by high performance liquid chromatography after a single injection of 0.5 mg/kg, and neuromuscular effects were evaluated by the single twitch method. With regard to pharmacokinetic or pharmacodynamic parameters, we found no statistically significant differences between normal and anephric patients. We conclude that during isoflurane anesthesia, anephric patients distribute and eliminate atracurium much as normal patients do.