Kinetics and dynamics of nifedipine after oral and sublingual doses.

Nifedipine is frequently administered by the sublingual route to provide rapid onset of intense effect, especially in patients in whom urgent reduction of elevated blood pressure is indicated. Previously available data, however, suggest that peak levels of nifedipine are higher and occur earlier when the drug is administered orally. Results of pharmacodynamic studies show that maximal hypotensive effects occur between 30 and 60 minutes after administration by either route, but that such effects are often achieved earlier when the drug is given orally. Recent work implies that the absorption of nifedipine through the buccal mucosa is poor, if it occurs at all, and that the appearance of nifedipine in plasma requires delivery of the drug to the stomach for active absorption. The small time lag in absorption that may be attributed to the dissolution of the nifedipine capsule may be obviated by biting through the capsule and swallowing the contents; this bite-and-swallow approach to dosing provides the most rapid rise in plasma nifedipine concentrations, and produces peak levels well above those achieved with sublingual administration.