The haemodynamic effects of intravenous nifedipine in normotensive and hypertensive subjects.

The antihypertensive effects of intravenous nifedipine, given by bolus and 2 hour infusion, were studied at two dose levels in seven hypertensive (mean BP 178/114 mmHg) and five age-matched normotensive controls (mean BP 128/81 mmHg). Nifedipine significantly reduced systolic and diastolic blood pressure in the hypertensive patients by approximately 20%, but not in the normotensive controls. Similar changes in heart rate and forearm blood flow were seen after bolus injection in both groups, but these were not sustained during infusion. Intravenous nifedipine may be a useful acute treatment for hypertensive emergencies.