Onset and duration of action of rocuronium in children receiving chronic anticonvulsant therapy

The onset and time course of action of rocuronium in normal children and ch ildren receiving anticonvulsant drugs for prolonged periods was characteriz ed. A single bolus dose of 0.6 mg.kg(-1) rocuronium was administered i.v. t o seven nonepileptic patients on no medication, and eight patients on chron ic anticonvulsant therapy consisting of either phenytoin, carbamazepine, or both who were age and weight matched. Neuromuscular transmission was monit ored by the evoked compound electromyography of the thenar muscles using tr ain of four stimulation every 20 s. Recovery times of the first twitch to 1 0%, 25%, 50%, 75% and 100% of baseline values and recovery index were obtai ned. The onset times were 1.05 +/- 0.5 and 1.41 +/- 0.5 min for the control and anticonvulsant groups respectively and were not significantly differen t. Children receiving chronic anticonvulsant therapy had significantly shor ter recovery index than the control group (control 10.4 +/- 5.1 min, antico nvulsant 4.8 +/- 1.7 min, P < 0.05). Furthermore, the duration of recovery to 10%, 50%, 75% and 100% of baseline T-1 values was less in the anticonvul sant drug group. Our data confirm resistance to rocuronium in children on c hronic anticonvulsant drugs.