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Labetalol and hydrochlorothiazide in hypertension. Labetalol/Hydrochlorothiazide Multicenter Study Group
Insights
Labetalol effectively lowers blood pressure when added to hydrochlorothiazide for essential hypertension. This combination therapy proved safe and beneficial for diverse patient groups.
Area of Science:
- Cardiology
- Pharmacology
Background:
- Essential hypertension is a prevalent cardiovascular condition requiring effective management.
- Hydrochlorothiazide (HCTZ) is a common first-line antihypertensive, but some patients require additional therapy.
Purpose of the Study:
- To evaluate the efficacy and safety of labetalol as an add-on therapy to hydrochlorothiazide (HCTZ) in patients with essential hypertension.
- To compare labetalol plus HCTZ versus placebo plus HCTZ.
Main Methods:
- Multicenter, randomized, double-blind, parallel comparison study.
- Patients received HCTZ, then were randomized to add-on labetalol or placebo.
- Blood pressure was measured supine and standing during treatment phases.
Main Results:
- Labetalol significantly reduced supine (10/9 mm Hg) and standing (17/13 mm Hg) blood pressure compared to placebo.
- Labetalol efficacy was consistent across racial groups (Blacks and Whites).
- Suggestive evidence indicated better response in women and older adults (>55 years).
Conclusions:
- Labetalol is a safe and effective second-line antihypertensive agent for moderate to severe essential hypertension inadequately controlled by HCTZ alone.
- Rhinitis was the most frequent side effect associated with labetalol.
- The findings support labetalol's role in managing resistant hypertension.
Abstract:
This study was a multicenter, randomized, double-blind, parallel comparison of labetalol vs. placebo added to hydrochlorothiazide (HCTZ) for the treatment of essential hypertension. The study consisted of 2 to 4 weeks of placebo and 3 to 7 weeks of HCTZ, 25 mg twice a day. Both of these first two phases were single blind. Subjects whose standing diastolic blood pressure remained greater than 95 mm Hg while taking HCTZ were randomized to receive either labetalol or matching placebo in addition to the HCTZ. Labetalol was started at 100 mg twice a day; the dose was increased every 2 weeks to a maximum of 400 mg twice a day. Subjects continued taking their maximum tolerated labetalol dose for another 4 weeks during the final phase of the study. Blood pressure fell 10/9 mm Hg supine and 17/13 mm Hg standing after the addition of labetalol (n = 83) and 3/4 and 5/5 mm Hg, respectively, after placebo (n = 91). Labetalol was equally effective in blacks and whites. There was suggestive evidence that women responded better to the combined therapy than did men, and that people greater than 55 years old responded better than those less than 55 years old. Five subjects receiving labetalol and one receiving placebo were dropped from the study because of side effects. Rhinitis was the only adverse effect reported significantly more often with labetalol than with placebo. We conclude that labetalol is a safe and effective step II antihypertensive for patients with moderate to moderately severe hypertension that does not respond adequately to HCTZ alone.