Behavioral performance effects of nifedipine in normotensive baboons: single dosing.

The effects of single oral doses of the calcium channel blocker nifedipine were assessed on performance of a simultaneous color match-to-sample task in three normotensive baboons. Both accuracy of color matching, and speed and latency of response were measured 30 min after administration of 0.10, 0.34, 0.57, and 1.7 mg/kg and vehicle, with each dose tested on three occasions in randomized order. Systolic and diastolic blood pressures also were measured after testing sessions. Maximal decreases in systolic blood pressures (mean of three subjects = -4.56 mmHg) were obtained after ingestion of the 0.57 mg/kg dose. Nifedipine produced dose-related changes in choice reaction times with a trend toward increased reaction times of approximately 5% obtained at 0.34 and 1.7 mg/kg. A reversal of effect was noted at 0.57 mg/kg such that smaller changes in reaction times were obtained, suggesting a lack of correlation between blood pressure and behavioral performance changes. These results indicate that nifedipine administered in single doses to patients with hypertensive crisis is unlikely to produce large impairments in these aspects of sensory and motor functioning.