Serum concentrations and effects of (±)‐nicardipine compared with nifedipine in a population of healthy subjects

The dihydropyridine calcium antagonist (±)‐nicardipine shares some of the pharmacologic properties of the dihydropyridine prototype nifedipine. To compare them, serum concentrations and cardiovascular effects of 10 mg nifedipine and 20 mg (±)‐nicardipine were evaluated at 1, 2, and 3 hours after oral intake in a randomized, crossover, single‐blind study involving 79 healthy volunteers. (±)‐Nicardipine serum concentrations were much lower than those of nifedipine, indicating a greater hepatic first‐pass metabolism of (±)‐nicardipine. There was a significant correlation between serum concentrations of both drugs. The frequency distributions of nifedipine and (±)‐nicardipine AUC(0–3), heart rate increase, and mean arterial pressure decrease showed no bimodality. This does not confirm the proposed polymorphism of nifedipine oxidation. Concentration‐effect plots indicate that (±)‐nicardipine is more potent than nifedipine but shows comparable efficacy in blood pressure reduction. Clinical Pharmacology and Therapeutics (1990) 48 155–160; doi: 10.1038/clpt.1990.130