The plasma concentrations of isosorbide 5-mononitrate (5-ISMN) administered in an extended-release form to patients with acute myocardial infarction.

Eighteen patients with acute myocardial infarction (AMI) followed the same extended-release isosorbide 5-mononitrate dosage regimen as was used in the Fourth International Study of Infarct Survival (ISIS-4). Plasma drug concentrations, blood pressure and heart rate were measured over 5 to 7 days following acute and repeated administrations. After the initial 30 mg dose on the first day of infarction, mean +/- standard deviation Cmax was 1237 +/- 284 nmol l-1 with a median tmax of 4 h (range 1 to 10 h). Following the last 60 mg dose, Cmax was 2685 +/- 497 nmol l-1 with a median tmax of 4 h (2 to 7 h). The plasma concentrations of this extended-release 5-ISMN in patients with acute myocardial infarction were similar to those seen in studies with healthy volunteers. However, drug absorption following the acute dose was protracted in some patients, possibly due to the concomitant administration of morphine. The kinetics of 5-ISMN at steady state were similar for all patients, and none showed protracted 5-ISMN absorption.