Cisatracurium pharmacodynamics in patients with oculopharyngeal muscular dystrophy

The pharmacodynamics of muscle relaxants in patients with oculopharyngeal muscular dystrophy (OPMD) have never been studied. We designed this study to compare the pharmacodynamics of cisatracurium in OPMD patients versus a control group. Forty patients were enrolled: 20 OPMD patients requiring general anesthesia for cricopharyngeal myotomy and 20 age-matched controls undergoing an operation of similar duration and expected blood loss. Anesthesia was standardized, and both groups received a bolus of cisatracurium 0.1 mg/kg. Onset time, time to 10% T1 recovery, and the intervals 10%, 25% and 25%-75% were calculated for both groups. A subgroup analysis was performed in patients with a more severe form of OPMD. Demographic and intraoperative data were similar. Onset time was significantly longer in OPMD patients compared with the control group (4.6 +/- 1.5 min versus 3.4 +/- 1.0 min; P = 0.001). There was no difference in recovery times or indices between groups, regardless of the severity of the disease. In conclusion, there was no difference in the duration of a cisatracurium-induced neuromuscular block between OPMD patients and a control group. A delayed onset of action of the drug may occur.