Non-interaction between nifedipine and digoxin.

In order to evaluate a possible interaction between digoxin and nifedipine, we studied steady state digoxin pharmacokinetics before and during oral coadministration of nifedipine in eight healthy subjects. Mean plasma digoxin concentration was 0.68 +/- 0.15 ng/ml during control conditions versus 0.74 +/- 0.13 ng/ml (NS) after two weeks of nifedipine coadministration. Nifedipine caused no significant changes in either renal digoxin clearance (173.6 +/- 25.9 versus 173.1 +/- 33.2 ml/min) or 24-hour urinary recovery of digoxin (164.7 +/- 25.7 versus 183.8 +/- 29.2 micrograms/24 hrs). Our findings support earlier observations that nifedipine coadministration is not associated with any significant alteration of digoxin pharmacokinetics.