Pharmacokinetic and pharmacodynamic interactions during multiple‐dose administration of nisoldipine and propranolol

Objectives The pharmacokinetic and pharmacodynamic interactions after 7 days of oral treatment with nisoldipine (10 mg twice daily) and propranolol (80 mg twice daily) were investigated in a partially randomized, placebo‐controlled crossover study of 12 healthy volunteers. Methods At the end of each treatment period, pharmacokinetic parameters were measured, along with blood pressure, heart rate, cardiac function, systemic hemodynamics, plasma catecholamines, forearm blood flow, and apparent hepatic blood flow (estimated by the clearance of indocyanine green dye). Results After 7 days of treatment with nisoldipine and propranolol, neither drug altered the other's bioavailability or elimination parameters, and propranolol did not change the area under the plasma concentration—time curve of nisoldipine's metabolite, N‐9425. Nisoldipine alone increased apparent hepatic blood flow and forearm blood flow compared with the other treatment groups but, with the addition of propranolol, both of these parameters were similar to those in the placebo group. Changes in the other hemodynamic parameters were consistent with the known effects of these drugs, and no differences in plasma catecholamine levels were detected. Conclusions In contrast to the findings with single‐dose treatment, administration of the combination of nisoldipine and propranolol for 7 days is not associated with any measurable kinetic interactions, although significant hemodynamic interactions do occur. Clinical Pharmacology and Therapeutics (1994) 55 , 661–669; doi: 10.1038/clpt.1994.83