Nilvadipine is absorbed rapidly and completely and its absolute bioavailability is about 14-19% because of its high first-pass metabolism. Maximum plasma levels and the extent of bioavailability increase proportionally with the dose.
Nilvadipine is mainly excreted via the kidney as inactive metabolites. Slow tissue redistribution is probably the reason for the terminal elimination half-life of 15-20 h. There was a good correlation between the estimated tissue concentration and the reduction in blood pressure in patients. The use of the sustained-release pellet formulation can prevent plasma level peaks and thereby lessen the typical side effects of
dihydropyridine calcium antagonists. The pharmacokinetics of
nilvadipine were not affected by impaired renal function, and although the bioavailability was increased in
liver cirrhosis, there was no accumulation after repeated doses. There was no effect on plasma
digoxin levels. The plasma concentration of
nilvadipine can be affected by either activation or inhibition of the
cytochrome P450 system. The use of a sustained-release once-a-day formulation to lower the peaks in plasma levels along with
nilvadipine's long terminal half-life means that this well-tolerated
pharmaceutical formulation can be employed in clinical trials for the treatment of
hypertension and expected to work over 24 h.