Captopril And Hydrochlorothiazide

Brand Names: Captopril And Hydrochlorothiazide

Drug Class: Angiotensin Converting Enzyme Inhibitor

Overview

DESCRIPTION Captopril and hydrochlorothiazide tablets, USP for oral administration combines two antihypertensive agents: captopril and hydrochlorothiazide. Captopril, the first of a new class of antihypertensive agents, is a specific competitive inhibitor of angiotensin I-converting enzyme (ACE), the enzyme responsible for the conversion of angiotensin I to angiotensin II.

Mechanism of Action

CLINICAL PHARMACOLOGY Captopril : Mechanism of Action : The mechanism of action of captopril has not yet been fully elucidated. Its beneficial effects in hypertension and heart failure appear to result primarily from suppression of the renin-angiotensin-aldosterone system. However, there is no consistent correlation between renin levels and response to the drug. Renin, an enzyme synthesized by the kidneys, is released into the circulation where it acts on a plasma globulin substrate to produce angiotensin I, a relatively inactive decapeptide. Angiotensin I is then converted by angiotensin converting enzyme (ACE) to angiotensin II, a potent endogenous vasoconstrictor substance.

Indications

  • INDICATIONS & USAGE Captopril and hydrochlorothiazide tablets are indicated for the treatment of hypertension. The blood pressure lowering effects of captopril and thiazides are approximately additive. This fixed combination drug may be used as initial therapy or substituted for previously titrated doses of the individual components. When captopril and hydrochlorothiazide are given together it may not be necessary to administer captopril in divided doses to attain blood pressure control at trough (before the next dose).

Common Doses

  • 25 mg
  • 15 mg
  • 50 mg
  • 150 mg

Dosage

DOSAGE & ADMINISTRATION DOSAGE MUST BE INDIVIDUALIZED ACCORDING TO PATIENT'S RESPONSE. Captopril and hydrochlorothiazide tablets may be substituted for the previously titrated individual components. Alternatively, therapy may be instituted with a single tablet of captopril and hydrochlorothiazide 25 mg/15 mg taken once daily. For patients insufficiently responsive to the initial dose, additional captopril or hydrochlorothiazide may be added as individual components or by using captopril and hydrochlorothiazide tablets 50 mg/15 mg, 25 mg/25 mg or 50 mg/25 mg, or divided doses may be used.

Black Box Warning

BOXED WARNING USE IN PREGNANCY When used in pregnancy during the second and third trimesters, ACE Inhibitors can cause injury and even death to the developing fetus. When pregnancy is detected, captopril and hydrochlorothiazide should be discontinued as soon as possible. See WARNINGS: Captopril: Fetal/Neonatal Morbidity and Mortality .

Contraindications

  • CONTRAINDICATIONS Captopril : This product is contraindicated in patients who are hypersensitive to captopril or any other angiotensin-converting enzyme inhibitor (e.g., a patient who has experienced angioedema during therapy with any other ACE inhibitor). Hydrochlorothiazide : Hydrochlorothiazide is contraindicated in anuria. It is also contraindicated in patients who have previously demonstrated hypersensitivity to hydrochlorothiazide or other sulfonamide-derived drugs.

Side Effects

  • ADVERSE REACTIONS Captopril : Reported incidences are based on clinical trials involving approximately 7000 patients. Renal : About one of 100 patients developed proteinuria (see WARNINGS ). Each of the following has been reported in approximately 1 to 2 of 1000 patients and are of uncertain relationship to drug use: renal insufficiency, renal failure, nephrotic syndrome, polyuria, oliguria, and urinary frequency. Hematologic : Neutropenia/agranulocytosis has occurred (see WARNINGS ). Cases of anemia, thrombocytopenia, and pancytopenia have been reported.

Interactions

  • Drug Interactions: Captopril : Hypotension—Patients On Diuretic Therapy : Patients on diuretics and especially those in whom diuretic therapy was recently instituted, as well as those on severe dietary salt restrictions or dialysis, may occasionally experience a precipitous reduction of blood pressure usually within the first hour after receiving the initial dose of captopril. The possibility of hypotensive effects with captopril can be minimized by either discontinuing the diuretic or increasing the salt intake approximately one week prior to initiation of treatment with captopril or...