Losartan and hydrochlorothiazide

Mechanism of action

Angiotensin II receptor blocker + thiazide diuretic (fixed-dose combination)

In plain language

Combines two blood pressure medicines in one tablet: losartan, which blocks a hormone receptor that narrows blood vessels, and hydrochlorothiazide, a diuretic that helps the kidneys remove extra salt and water from the blood.

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ClinicalPlain language

How it works

HYZAAR combines losartan, an angiotensin II receptor blocker (ARB), and hydrochlorothiazide, a thiazide diuretic. Per the FDA label, losartan and its active metabolite selectively block the binding of angiotensin II -- the primary vasoconstrictor hormone of the renin-angiotensin system -- to the AT1 receptor found in vascular smooth muscle and the adrenal gland, blocking both its vasoconstrictor and aldosterone-secreting effects. Hydrochlorothiazide acts independently on the kidney's distal tubule, increasing excretion of sodium and chloride to reduce blood volume. The label notes the mechanism of thiazides' antihypertensive effect itself is not fully established, but the two drugs' effects are additive.

Therapeutic applications

HYZAAR is FDA-indicated for the treatment of hypertension, to lower blood pressure, and for the reduction of the risk of stroke in patients with hypertension and left ventricular hypertrophy -- though the label notes evidence that this stroke-risk benefit does not apply to Black patients.

Class

Fixed-dose combination

Therapeutic area

Cardiovascular

Source

FDA label (DailyMed) ↗