ETHNIC-DIFFERENCES IN THE PHARMACOKINETICS OF ORAL NIFEDIPINE

1 The pharmacokinetics of a single oral dose of 20 mg nifedipine, given as capsules, has been compared in five South Asian volunteers with data for 27 Caucasian volunteers. 2 The area under the plasma concentration-time curve (AUC) of nifedipine was three fold higher in South Asians (989 +/- 166 ng ml-1 h) than in Caucasians (323 +/- 116 ng ml-1h). 3 The ratio of the AUC of nifedipine to that of the nitropyridine analogue, which is formed largely as a first pass metabolite, was significantly higher in South Asians (4.6 +/- 1.9) than in Caucasians (2.3 +/- 1.1) indicating a lower first pass metabolism in South Asians. 4 The terminal half-lives of nifedipine and the nitropyridine metabolite were significantly greater in South Asians than in Caucasians. 5 Consumption of a spicy curry diet for 3 days by Caucasians did not significantly affect the pharmacokinetics of a single oral dose of nifedipine. 6 The treatment of patients of South Asian origin with nifedipine should be initiated with lower doses than would be given to Caucasians.