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Abstract
The antihypertensive effects of oral labetalol, a new alpha- and beta-adrenergic blocking
agent, and metoprolol, a relatively beta1 selective adrenergic blocker, were evaluated in 91 patients with mild to moderate
hypertension (standing diastolic blood pressure of 90 to 115 mm Hg) in a double-blind
parallel group multicenter clinical trial. The effects of the two drugs on plasma
lipids and lipoprotein fractions were also assessed. Following a four-week placebo
phase, 44 patients were randomized to receive labetalol and 47 metoprolol. During
a four-week titration phase, the labetalol dose was increased from 100 mg twice daily
to a maximum of 600 mg twice daily to achieve a standing diastolic blood pressure
of 90 mm Hg that was decreased by 10 mm Hg or more. Metoprolol was titrated from 50
mg to 200 mg twice daily. An eight-week maintenance period followed during which hydrochlorothiazide
could be added. At the end of the maintenance phase, the doses of labetalol and metoprolol
were tapered over a two to four day period after which patients received a placebo
for one week. Blood pressure in the supine and standing position was measured at each
visit. Labetalol and metoprolol both significantly (p < 0.01) lowered the supine and
standing blood pressure from baseline with no significant difference found between
the two treatment groups. Both drugs lowered the heart rate; however, the rate-lowering
effect was significantly greater with metoprolol (p < 0.01). There were no significant
effects of either drug on plasma lipids or lipoprotein fractions. Fatigue was the
most frequently reported complaint with both drugs. Dizziness, dyspepsia, and nausea
were more common with labetalol; bradycardia was more common with metoprolol. There
was no blood pressure “overshoot” after withdrawing drug treatment; however, a heart
rate “overshoot” was seen after metoprolol was tapered off and stopped. Labetalol
is as safe and effective as metoprolol in the treatment of patients with mild to moderate
hypertension.
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Article info
Footnotes
☆This study was supported in part by a grant from Schering Corporation, and Glaxo, Incorporated.
Identification
Copyright
© 1983 Published by Elsevier Inc.
