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Captopril / Hydrochlorothiazide

Pronunciation: KAP-toe-prill/high-droe-klor-oh-THIGH-uh-zide
Class: Antihypertensive combination

Trade Names

- Tablets captopril 25 mg/hydrochlorothiazide 15 mg
- Tablets captopril 25 mg/hydrochlorothiazide 25 mg
- Tablets captopril 50 mg/hydrochlorothiazide 15 mg
- Tablets captopril 50 mg/hydrochlorothiazide 25 mg



Competitively inhibits angiotensin I-converting enzyme, resulting in the prevention of angiotensin I conversion to angiotensin II, a potent vasoconstrictor that also stimulates aldosterone secretion. This action results in a decrease in sodium and fluid retention, increase in diuresis, and a decrease in BP.

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Increases chloride, sodium, and water excretion by interfering with transport of sodium ions across renal tubular epithelium.

Indications and Usage

Treatment of hypertension.


Anuric patients; history of angioedema; patients hypersensitive to captopril or any other ACE inhibitor, hydrochlorothiazide, or other sulfonamide derivative.

Dosage and Administration


PO captopril/hydrochlorothiazide may be substituted for previously titrated individual components. Alternatively, therapy may be started with a single captopril/hydrochlorothiazide tablet (25 mg captopril combined with 15 mg hydrochlorothiazide) every day. For patients not responding sufficiently, the dose may be titrated upward, usually at 6-wk intervals. Maximum daily dose should not exceed 150 mg of captopril or 50 mg of hydrochlorothiazide.

General Advice

Give dose 1 h before or 2 h after meals.


Store tablets at controlled room temperature (59° to 86°F). Keep container tightly closed and protect from moisture.

Drug Interactions

Alcohol, barbiturates (eg, phenobarbital), narcotics

Orthostatic hypotension may be potentiated.

Anticoagulants (eg, warfarin)

Anticoagulant effect may be decreased.

Antidiabetic agents (eg, insulin, sulfonylureas)

Dosage adjustment may be necessary because of possible hydrochlorothiazide-induced elevation in blood glucose levels.

Antigout agents (eg, probenecid)

Dosage adjustment may be necessary because of possible hydrochlorothiazide-induced elevation in blood uric acid levels.

Cardiac glycosides (eg, digoxin)

Possible digitalis toxicity associated with hypokalemia.

Cholestyramine, colestipol

May impair the absorption of hydrochlorothiazide.


Reduces bioavailability of captopril.


Plasma levels of lithium may be elevated, increasing the risk of toxicity.


May reduce the natriuretic and antihypertensive effect of hydrochlorothiazide.

Potassium supplements, potassium-sparing diuretics (eg, spironolactone)

Increased risk of hyperkalemia.

Nondepolarizing muscle relaxants (eg, tubocurarine)

Effects may be increased.

Laboratory Test Interactions


May cause false-positive urine acetone test.


May cause diagnostic interference of bentiromide test; may decrease serum protein-bound iodine levels without signs of thyroid disturbances; may cause diagnostic interference of serum electrolyte levels, blood and urine glucose levels, serum bilirubin levels, and serum uric acid levels.

Adverse Reactions



Hypotension; tachycardia; chest pain; palpitations; angina pectoris; MI; Raynaud syndrome; CHF; cardiac arrest; cerebrovascular accident; rhythm disturbances; orthostatic hypotension; syncope.


Orthostatic hypotension; necrotizing angiitis.



Ataxia; confusion; depression; nervousness; somnolence.


Dizziness; vertigo; paresthesia; headache; xanthopsia; restlessness.



Rash; pruritus; pemphigoid-like lesion; photosensitivity; bullous pemphigus; erythema multiforme (including Stevens-Johnson syndrome); exfoliative dermatitis.


Purpura; photosensitivity; rash; urticaria.



Glossitis; blurred vision.


Transient blurred vision.



Dysgeusia; pancreatitis; dyspepsia.


Anorexia; gastric irritation; nausea; vomiting; cramping; diarrhea; constipation; jaundice (intrahepatic cholestatic jaundice); pancreatitis; sialadenitis.



Proteinuria; gynecomastia; impotence.





Neutropenia; agranulocytosis; anemia; thrombocytopenia; pancytopenia; eosinophilia; aplastic anemia; hemolytic anemia.


Leukopenia; agranulocytosis; thrombocytopenia; aplastic anemia; hemolytic anemia.



Jaundice; hepatitis, including necrosis and cholestasis.



Hyponatremia; hyperkalemia.


Hyperglycemia; hyperuricemia; hypokalemia; hyponatremia.



Bronchospasm; eosinophilic pneumonitis; rhinitis; persistent dry cough.


Respiratory distress, including pneumonitis.



Fever; arthralgia; angioedema; anaphylactoid reactions; asthenia; myalgia; myasthenia; syndrome including fever, myalgia, arthralgia, interstitial nephritis, vasculitis, rash or other dermatologic symptoms, eosinophilia, and elevated erythrocyte sedimentation rate.


Muscle spasm; weakness; fever; anaphylactic reactions.



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, discontinue therapy as soon as possible.


Blood sugar

Monitor blood sugar in diabetic patient when drug is started or dose is changed. Report significant changes to health care provider.


Monitor and record BP and pulse. Should hypotension result, hold medication and notify health care provider.

Serum electrolytes

Ensure that serum electrolytes are monitored periodically.


Ensure that WBC with differential is determined prior to starting treatment, every 2 wk for 3 mo, and periodically thereafter in hypertensive patients with renal function impairment or CHF.


Category D (second and third trimester); Category C (first trimester). ACE inhibitors (eg, captopril) can cause injury or death to fetus if used during second or third trimester. When pregnancy is detected, discontinue as soon as possible.


Excreted in breast milk.


Safety and efficacy not established.

Renal Function

Use with caution.

Hepatic Function

Use with caution.


Use with extreme caution in patients with hereditary angioedema. Angioedema associated with laryngeal edema may be fatal.


Decreases in BP may occur, especially in salt- or volume-depleted patients as a result of dialysis, prolonged diuretic therapy, dietary salt restriction, diarrhea, or vomiting. Volume and salt depletion should be corrected before initiating therapy with benazepril/hydrochlorothiazide.


Has occurred with other ACE inhibitors.



Dehydration, electrolyte disturbances, hypotension, CNS depression, lethargy, coma.

Patient Information

  • Advise patient to take every day as prescribed. Advise patient that if more than 1 daily dose is prescribed to take the second dose late in the afternoon to avoid excessive urination at night.
  • Instruct patient to take each dose at least 1 h before meals.
  • Advise patient to try to take each dose at about the same time each day if possible.
  • Inform patient that drug controls, but does not cure, hypertension and to continue taking drug as prescribed even when BP is not elevated.
  • Caution patient not to change the dose or stop taking unless advised by health care provider.
  • Instruct patient to continue taking other BP medications as prescribed by health care provider.
  • Instruct patient in BP and pulse measurement skills.
  • Advise patient to monitor and record BP and pulse at home and to inform health care provider if abnormal measurements are noted. Also advise patient to take record of BP and pulse to each follow-up visit.
  • Caution patient to avoid sudden position changes to prevent orthostatic hypotension.
  • Instruct patient to lie or sit down if experiencing dizziness or lightheadedness when standing.
  • Caution patient that inadequate fluid intake, excessive perspiration, diarrhea, or vomiting can lead to excessive fall in BP, resulting in lightheadedness or fainting.
  • Instruct diabetic patient to monitor blood glucose more frequently when drug is started or dose is changed and to inform health care provider of significant changes in readings.
  • Caution patient to avoid unnecessary exposure to UV light (eg, sunlight, tanning booths), use sunscreen, and wear protective clothing when exposed to UV light to avoid photosensitivity reaction.
  • Emphasize to hypertensive patient importance of other modalities on BP: weight control, regular exercise, smoking cessation, and moderate intake of alcohol and salt.
  • Instruct patient to stop taking drug and immediately report any of the following symptoms to health care provider: persistent cough; fainting; swelling of the face, lips, eyelids or tongue; sore throat; fever or other signs of infection; yellowing of skin or eyes; persistent nausea or vomiting; swelling of the feet or ankles.
  • Caution patient to not take any prescription or OTC medications, salt substitutes, or dietary supplements unless advised by health care provider.

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