A hypertensive urgency represents a moderate to severe elevation in systemic arterial pressure without immediate evidence of end-organ damage. Patients with hypertensive urgency do not require immediate lowering of blood pressure but may benefit from therapy within 24 hours. Gonzalez and associates conducted a randomized, double-blind trial to evaluate the dose response of the oral administration of labetalol (100 mg, 200 mg or 300 mg) on heart rate and systemic blood pressure in patients with hypertensive urgency and no end-organ evidence of hypertensive emergency.
A total of 255 patients who presented to an urban emergency department with hypertensive urgency were considered for inclusion in the study if they had a systolic blood pressure of 160 mm Hg to 240 mm Hg and a diastolic blood pressure of 110 mm Hg to 140 mm Hg. Patients were evaluated after 30 minutes of bed rest. Of the 255 patients, 219 were excluded. The most frequent reason for exclusion was spontaneous decrease in diastolic blood pressure to less than 110 mm Hg after bed rest.
Thirty-six patients with supine diastolic blood pressure of 110 mm Hg to 140 mm Hg after 30 minutes of bed rest were studied. The patients ranged in age from 23 to 67 years (mean age: 44 years). Thirty-four of the patients were black, and two were white. The patients were randomly assigned to receive 100 mg, 200 mg or 300 mg of orally administered labetolol. Each treatment group included 12 patients. Supine blood pressure and heart rate were measured manually and recorded hourly for four hours after administration of labetalol. Diastolic blood pressure of 100 mm Hg or less or a reduction of at least 30 mm Hg in diastolic blood pressure was considered treatment success.
The 100-mg dose of labetalol significantly reduced heart rate at three and four hours follow-up, compared with baseline measurements. The 300-mg dose significantly reduced heart rate at one, two and three hours follow-up. The 200-mg dose did not significantly affect heart rate. All three doses produced a significant decrease in systolic and diastolic blood pressures at one, two, three and four hours follow-up, compared with baseline measurements. At four hours follow-up, control of diastolic blood pressure was observed in 50 percent of the patients receiving the 100-mg dose, in 64 percent of the patients receiving the 200-mg dose and in 67 percent of those receiving the 300-mg dose. A comparison of the success rates of treatment showed a waning of response with the 100-mg dose of labetalol after four hours, compared with the response after two hours. No adverse effects were reported during the four-hour study period.
The authors conclude that in patients with hypertensive urgencies, labetalol is safe and effective when administered orally in doses of 100 mg to 300 mg. (Annals of Emergency Medicine, April 1991, vol. 20 p. 333.)
COPYRIGHT 1991 American Academy of Family Physicians
COPYRIGHT 2004 Gale Group
Contact
Home
A
Labetalol