Department of Clinical Pharmacy, College of Pharmacy, King Saud University, P.O.Box 2457, Riyadh 11451. Military Hospital, Riyadh, Kingdom of Saudi Arabia.The pharmacokinetics and pharmacodynamic effects of oral nifedipine were studied in five healthy
male Middle Eastern Arab subjects and their results were compared with those reported for other
populations. Each subject received a single 2* 10-mg dose under fasting conditions and plasma
concentrations were determined by a specific HPLC method. Heart rate and systolic and diastolic
blood pressure were also monitored. The elimination half-life, maximum plasma concentration
and time to maximum plasma concentration were found to be 3.20±0.21 h, 230.4±36.4 ng/ml and
0.95±0.23 h, respectively. Mean residence time (MRT) and operative clearance (CL/F) were
determined to be 3.82±0.67 h and 0.30±0.06 L/h.kg, respectively. Plasma concentrations in Middle
Eastern Arab subjects were similar to those reported for South Asians, Japanese and Nigerians,
but they were significantly higher than in Caucasians. The AUC and normalized AUC were 2.8
and 3.4 folds greater in Middle Eastern Arab subjects than in Caucasians. The hemodynamic
effects of nifedipine were comparable in all ethnic groups studied. In conclusion, Middle Eastern
Arab patients should be initiated with a lower dose than would be administered to Caucasians