The acute effect of sublingual nifedipine and isosorbide dinitrate on plasma viscosity in patients with acute myocardial infarction

The effect of sublingual nifedipine 10 mg (pierced capsule) and isosorbide dinitrate (ISDN) 5 mg on plasma viscosity (Pl.V) was investigated in 60 consecutive patients 7-10 days after hospitalization for acute myocardial infarction (AMI), who were randomized for either nifedipine (30 patients) or ISDN (30 patients). Pl.V, hematocrit (Htc), and erythrocyte sedimentation rate (ESR) were measured 20 minutes before and thereafter at 5, 10, and 30 min after drug administration while in the recumbent position. Blood pressure (BP) and heart rate (HR) were determined before each blood sample. In 18 patients (60%) Pl.V decreased by greater than 0.05 centipoise (Cp) after nifedipine (0.0953 +/- 0.033 Cp p less than 0.001 vs. initial values). After ISDN, Pl.V decreased by greater than 0.05 Cp (0.0933 +/- 0.036 Cp) in only 7 patients (23%). Systolic blood pressure (SBP) fell by 11.7 +/- 14.6 mmHg after nifedipine and by 16 +/- 14 mmHg after ISDN (nifedipine vs. ISDN = NS). Diastolic blood pressure (DBP) fell by 8 +/- 9.6 mmHg after ISDN and by 6.6 +/- 19.3 mmHg after nifedipine (nifedipine vs ISDN = NS). HR, ESR, and Htc did not change after drug administration. It is thus concluded from our study that nifedipine 10 mg sublingual has a significant Pl.V-lowering activity compared to sublingual ISDN 5 mg in patients with AMI.