Prescription ·Strong evidence ·Reviewed May 2026
Labetalol is a combined nonselective beta-adrenergic and selective alpha-1 adrenergic receptor blocker used to treat hypertension, including hypertensive emergencies and chronic hypertension in pregnancy. It is available in oral and intravenous forms and lowers blood pressure without typically causing reflex tachycardia. It is one of the preferred antihypertensives during pregnancy because of an extensive safety record.
The bottom line
Evidence rating strong. Most-documented uses: treatment of chronic essential hypertension, management of hypertension in pregnancy and preeclampsia, control of hypertensive emergencies and urgencies (intravenous). 4 sources indexed (1977–2021), with 3 interaction records on file.
Core mechanism
Labetalol blocks both beta-1 and beta-2 adrenergic receptors (nonselective beta blockade) and selectively blocks alpha-1 adrenergic receptors. Alpha-1 blockade produces peripheral arterial vasodilation and reduces systemic vascular resistance, while beta blockade attenuates the reflex sympathetic drive (tachycardia and increased cardiac output) that vasodilation would otherwise trigger. The net effect is a fall in blood pressure with relatively little change in resting heart rate and cardiac output. The oral alpha-to-beta blocking ratio is approximately 1:3 and the intravenous ratio is approximately 1:7.1,4
Labetalol is well absorbed orally but undergoes extensive first-pass hepatic metabolism, giving an absolute bioavailability of roughly 25 percent. Food increases bioavailability somewhat, so taking it consistently with or without food is advised; dosing with meals can improve tolerability.2
Nutrients this medication can lower over time, and what to replace.
Like other beta-adrenergic blocking agents, labetalol can inhibit Coenzyme Q10 (ubiquinone)-dependent enzymes and reduce CoQ10-related mitochondrial activity, which may lower tissue and circulating CoQ10. CoQ10 shares structural similarity with the beta-blocker pharmacophore, and beta-blockade has been associated with reduced CoQ10-dependent respiratory chain function; this is considered a class effect rather than one specific to labetalol.
L-Citrulline may add to the blood-pressure-lowering effect of Labetalol.
Recommendation: Monitor blood pressure and dizziness, especially during dose changes; stop the supplement and seek advice if syncope, falls, or symptomatic hypotension occurs.
Magnesium Glycinate may add to the blood-pressure-lowering effect of Labetalol.
Recommendation: Monitor blood pressure and dizziness, especially during dose changes; stop the supplement and seek advice if syncope, falls, or symptomatic hypotension occurs.
Berberine may lower glucose, while beta blockers can mask adrenergic warning signs of hypoglycemia such as tachycardia.
Recommendation: Use glucose monitoring if diabetic or taking glucose-lowering drugs; do not rely only on palpitations as a hypoglycemia warning sign.
Numbered references. Citations throughout the page link here.
Beta blockade can mask sympathetic warning signs of hypoglycemia, though sweating may persist.
Labetalol produces dose-related falls in blood pressure through combined alpha-1 and beta blockade without substantial reflex tachycardia.
Labetalol is recommended as a first-line agent for acute and chronic management of hypertension in pregnancy.
Several beta-blocking drugs inhibited CoQ10-dependent mitochondrial enzymes in vitro, a proposed mechanism for reduced CoQ10 status.
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