Captopril and hydrochlorothiazide for hypertension management

Captopril and hydrochlorothiazide tablets combine two blood pressure-lowering medicines into one oral tablet. Captopril belongs to a class called ACE inhibitors that help relax blood vessels by blocking an enzyme, while hydrochlorothiazide is a thiazide diuretic that increases fluid and salt elimination by the kidneys. This combination is approved to treat hypertension in adults, improving blood pressure control through complementary mechanisms.

This medication is indicated for the treatment of hypertension (high blood pressure) in adults. It may be used as initial therapy or to replace individually dosed components. It is appropriate for patients with normal kidney function or mild renal impairment. However, caution and specialist evaluation is recommended in patients with impaired renal function or collagen vascular disease before use due to increased risk of side effects.

captopril, hydrochlorothiazide

Captopril works by inhibiting angiotensin-converting enzyme (ACE), which reduces the formation of angiotensin II, a substance that causes blood vessels to narrow and stimulates aldosterone release that retains sodium and fluid. Lowering angiotensin II relaxes blood vessels and decreases blood pressure.

Hydrochlorothiazide acts on the kidneys to decrease sodium and chloride reabsorption in the renal tubules, promoting diuresis (increased urine output). This salt and fluid loss lowers blood volume, contributing to blood pressure reduction. The combination enhances antihypertensive effects through complementary pathways.

The recommended starting dose for adults with hypertension is one tablet containing 25 mg captopril and 15 mg hydrochlorothiazide, taken once daily. Depending on blood pressure response, doses may be adjusted using tablets with higher captopril (50 mg) and/or hydrochlorothiazide (25 mg) content or by separating components for individual dose titration.

Captopril tablets should be taken approximately one hour before meals to optimize absorption, as food decreases captopril absorption by 30-40%. Hydrochlorothiazide can be taken with or without food.

Dosing adjustments may be needed in patients with impaired renal function or other risk factors. Regular monitoring of kidney function and blood electrolytes is advised.

Hypersensitivity to captopril, any other ACE inhibitor, or sulfonamide-derived drugs (for hydrochlorothiazide).

Hydrochlorothiazide is contraindicated in patients with anuria (inability to urinate).

Pregnancy: Use during the second and third trimesters can cause fetal injury or death. If pregnancy is detected, treatment should be discontinued as soon as possible.

Neutropenia/Agranulocytosis: Rare but serious reduction of white blood cells has been reported, especially in patients with renal impairment or collagen vascular disease. Close monitoring of blood counts is necessary in these groups.

Angioedema: Swelling of the face, lips, tongue, glottis, or larynx can occur and may be life-threatening. Immediate medical attention and discontinuation of the drug are required.

Hypotension: Excessive blood pressure lowering can occur in volume-depleted patients, such as those on diuretics or with heart failure.

Hepatic failure: Rare cases of severe liver injury have been reported; discontinue if jaundice or elevated liver enzymes occur.

Electrolyte imbalance: Hydrochlorothiazide can cause electrolyte disturbances, especially in patients with kidney dysfunction; regular electrolyte monitoring is recommended.

Common side effects: Persistent dry cough, dizziness, hypotension, fatigue.

Serious side effects: Angioedema (swelling of face/tongue/throat), neutropenia/agranulocytosis (low white blood cell count), severe hypotension, renal impairment, hepatic injury.

Captopril may increase serum potassium; use caution with potassium supplements, potassium-sparing diuretics, or potassium-containing salt substitutes.

ACE inhibitors can cause hypersensitivity reactions during hemodialysis with high-flux membranes; consider alternative dialysis or medication.

Use with lithium is generally not recommended due to risk of lithium toxicity.

Pregnancy: ACE inhibitors, including captopril, can cause fetal harm when used during the second and third trimesters. Discontinue as soon as pregnancy is detected.

Breastfeeding: Data on safety during lactation are not provided in this label.

Manifestations of overdose may include severe hypotension and electrolyte imbalances. Treatment is supportive with careful monitoring of blood pressure and electrolytes. Hemodialysis removes captopril in adults but efficacy in neonates or children is unknown.

Store at controlled room temperature. Protect from moisture and light. Follow specific manufacturer storage instructions on the packaging.