THE INFLUENCES OF DOSE AND ETHNIC-ORIGINS ON THE PHARMACOKINETICS OF NIFEDIPINE

The pharmacokinetics of nifedipine capsules was investigated in health y young Caucasian and South Asian subjects. Both the area under the pl asma concentration-time curve (AUC) and terminal half-life of nifedipi ne were significantly higher in South Asians compared with Caucasian s ubjects after single oral doses of 10 and 20 mg. The AUC and half-life values of the nitropyridine metabolite were also higher in South Asia ns than in Caucasian subjects. The serum protein binding of nifedipine was similar in the two groups. The pharmacokinetics were essentially linear in both Caucasian subjects (0 to 30 mg; n = 27) and South Asian s (0 to 20 mg; n = 16). There was no indication of a separate subgroup of Caucasian subjects with high AUC values equivalent to the poor met abolizers reported previously. Pharmacodynamic modeling for South Asia ns gave estimates comparable to those previously reported in Caucasian subjects. Patients of South Asian origin may require lower doses of n ifedipine.