Nifedipine in the management of hypertensive emergencies: report of two cases and review of the literature.

Calcium channel blockers are assuming increasingly important roles in the practice of emergency medicine. Two cases and a review of the literature relating to treatment of hypertensive emergencies with nifedipine are presented. Nifedipine has a rapid onset of action (buccal, 10-15 minutes; oral, 30-45 minutes) and peak effect (buccal, 30 minutes, oral, 60 minutes). The duration of effects is four to six hours regardless of the route of administration, with a mean arterial pressure reduction of 21.6% (248/134 mm Hg to 165/87 mm Hg). In patients with severe hypertension and left ventricular failure, a consistent reduction in systemic vascular resistance (2,088 dynes/sec/cm-5 to 1242 dynes/sec/cm-5) and cardiac index (2.76 l/min/m2 to 3.77 l/min/m2) has been reported. The patients in this study had severe hypertension (systolic blood pressure greater than 180 mm Hg, diastolic blood pressure greater than 120 mm Hg) and end organ involvement (including heart failure, left ventricular strain, headache, confusion, dizziness, and shortness of breath). Nifedipine (10 mg) was administered buccally with prompt reduction of blood pressure and resolution of the patients' symptoms. Nifedipine appears to be a safe, effective agent for the management of hypertensive emergencies. Its pharmacokinetic profile and routes of administration make it particularly valuable in the practice of emergency medicine.