Plasma concentration of diltiazem after oral administration in normal volunteers.

The plasma concentration and hemodynamics of diltiazem after oral administration of 90 mg were studied in nine normal volunteers. Diltiazem was rapidly absorbed within three hours, and mean peak plasma concentration was 93.3 +/- 12.6 ng/ml (mean +/- SE). The plasma level gradually declined soon after, and almost no diltiazem was determined in 24-hours. Heart rate and blood pressure decreased slightly but significantly (P less than 0.001 and P less than 0.005, respectively). No prolongation of PR interval was demonstrated.