Efficacy and safety of sublingual nifedipine in hypertensive emergencies.

Hypertensive emergencies are a diverse group of disorders characterized by a marked elevation of systemic arterial pressure that is associated with acute end-organ dysfunction. The efficacy and safety of sublingual nifedipine were evaluated in 16 men and 14 women (mean age 65 +/- 14 years) who had hypertensive emergencies. Before treatment, mean systolic blood pressure was 224 +/- 23 mm Hg, mean diastolic blood pressure was 125 +/- 18 mm Hg, and the average mean arterial pressure was 158 +/- 16 mm Hg. Administration of 10 or 20 mg of sublingual nifedipine initiated a smooth and predictable decline in blood pressure values within five minutes and produced a peak effect between 30 and 60 minutes. At 30 minutes, the decreases in the systolic blood pressure, diastolic blood pressure, and mean arterial pressure for the group were 49 +/- 24 mm Hg, 31 +/- 17 mm Hg, and 39 +/- 20 mm Hg, respectively, all of which were highly significant (p less than 0.001). By 60 minutes, nifedipine had decreased the diastolic blood pressure to less than 120 mm Hg in 97 percent of patients, less than 110 mm Hg in 93 percent, and less than 100 mm Hg in 67 percent. Fourteen patients required other antihypertensive medications within the first 12 hours for the antihypertensive effect to be maintained. In this group, the systolic, diastolic, and mean arterial pressures were significantly lower than baseline values (p less than 0.001) at the time that the other drugs were started (which occurred at a mean of 4.3 +/- 3.2 hours after entry into the study). The response to nifedipine correlated with the blood pressure value prior to treatment, but did not correlate with age, gender, value prior to treatment, but did not correlate with age, gender, or the type of hypertensive emergency. Twenty mg of nifedipine produced a significantly greater antihypertensive effect than did 10 mg during the first 20 minutes (176 +/- 15 mm Hg versus 201 +/- 18 mm Hg systolic; p = 0.009) and appeared to be more efficacious clinically. In only two of 30 patients (7 percent) was the blood pressure response considered inadequate, and all 10 patients with pulmonary edema or myocardial ischemia showed clinical improvement within 60 minutes of treatment. In one patient, flushing and another symptom suggestive of transient symptomatic hypotension developed after treatment with nifedipine. These results suggest that sublingual nifedipine is a safe, effective, and practical agent for treating patients with hypertensive emergencies.