Lack of impairment in skills related to driving after intramuscular administration of prilocaine or mepivacaine.

A saline placebo, 3 mg/kg of 2% plain prilocaine, and 3 mg/kg of 2% plain mepivacaine were injected into the deltoid muscles of 10 healthy subjects in a doubleblind, cross-over trial. Before and at 0.5, 1.5 and 3 h after injection, psychomotor skills related to driving were measured. When compared to the saline placebo, neither prilocaine nor mepivacaine impaired the parameters of psychomotor function measured. Blood concentrations of prilocaine were significantly (P less than 0.001) lower than those of mepivacaine during the whole observation period. It was concluded that in comparison to lidocaine, bupivacaine, or etidocaine, which have been tested previously and found to impair psychomotor performance, mepivacaine and, especially, prilocaine are the anaesthetic agents to be preferred when effects on central nervous system should be avoided, e.g. in outpatient practice.