Comparison of nitroglycerin with nifedipine in patients with hypertensive crisis or severe hypertension.
To determine whether nitroglycerin is as effective as nifedipine in lowering the blood pressure in severe hypertension and hypertensive crisis, two groups of 20 patients received in random sequence either 1.2 mg nitroglycerin sublingually or a 10-mg nifedipine capsule, which was chewed and swallowed. The blood pressure fell after 5 min in the nitroglycerin group from 211/122 mmHg to 171/95 mmHg and after nifedipine from 210/118 to 185/102 mmHg. The greater effect of nitroglycerin may result from faster absorption through the oral mucosa than through the small intestinal mucosa where nifedipine is primarily absorbed. After 15-20 min a satisfactory reduction in blood pressure was reached in both groups: 157/91 and 158/92 mmHg, respectively. After 30 min the heart rate in the nitroglycerin group had decreased from 83 to 80/min, but in the nifedipine group it had increased from 84 to 90/min. The reduction in blood pressure persisted up to 6 h. No significant differences in side effects were determined. Since a hypertensive crisis is usually accompanied by left ventricular failure, pulmonary edema, angina pectoris, or infarction, nitroglycerin has been definitively shown positively to influence these conditions, and preference should be given to nitroglycerin in the treatment of hypertensive crises.