Side effects and skills related to driving after intramuscular administration of bupivacaine and etidocaine.

Eleven healthy subjects were injected intramuscularly with a saline placebo, 1.3 mg/kg of 0.5% plain bupivacaine, or 2.6 mg/kg of 1.0% plain etidocaine in a double-blind cross-over fashion. Before and at 1/2, 2 and 4 h after injection, side effects were recorded, and psychomotor skills related to driving were measured. Fatigue, dizziness, and sore thighs were significantly more common with etidocaine than with bupivacaine or the saline solution. Bupivacaine significantly impaired eye-hand cooridination and flicker fusion discrimination during the whole observation period. Etidocaine impaired flicker fusion discrimination only. The subjects' adaption to darkness, sensitivity to brightness, and visual discrimination ability in bright counterlight remained unaltered after each treatment. The results suggest that such psychomotor performance as driving ability is impaired for at least 2 h after a patient receives 1.3 mg/kg of plain bupivacaine or 2.6 mg/kg of plain etidocaine intramuscularly.