Hydrochlorothiazide is a widely prescribed thiazide diuretic, recognized for its efficacy in managing hypertension and edema. It functions by promoting the excretion of sodium and water from the body, thereby reducing blood volume and peripheral vascular resistance. This medication is often utilized as a first-line treatment or in combination therapy, supported by decades of clinical evidence demonstrating its safety and effectiveness in diverse patient populations.

Features

• Active ingredient: Hydrochlorothiazide
• Drug class: Thiazide diuretic
• Available in oral tablet form (common strengths: 12.5 mg, 25 mg, 50 mg)
• Typically administered once daily
• Generic availability ensures cost-effectiveness
• Onset of diuretic action within 2 hours; peak effect at about 4 hours

Benefits

• Significantly lowers systolic and diastolic blood pressure, reducing cardiovascular risk
• Decreases edema associated with heart failure, renal dysfunction, or hepatic cirrhosis
• May reduce the risk of kidney stones in patients with hypercalciuria
• Often enables reduced dosing or discontinuation of other antihypertensive agents
• Supports long-term management with a well-established safety profile
• Contributes to overall fluid balance in conditions requiring diuresis

Common use

Hydrochlorothiazide is primarily indicated for the management of essential hypertension, either as monotherapy or in combination with other antihypertensive agents such as ACE inhibitors or beta-blockers. It is also prescribed for edema due to congestive heart failure, hepatic cirrhosis, renal dysfunction, or corticosteroid and estrogen therapy. Off-label uses may include treatment of nephrolithiasis in hypercalciuric patients and diabetes insipidus.

Dosage and direction

Dosage must be individualized based on patient response and indication. For hypertension, the typical starting dose is 12.5–25 mg once daily, which may be titrated to 50 mg daily if necessary. For edema, initial doses range from 25–100 mg daily, administered in single or divided doses; maintenance doses are often lower. Administration in the morning is recommended to avoid nocturia. Dosage adjustments are required in renal impairment—use is not recommended if eGFR is <30 mL/min.

Precautions

Monitor electrolytes (particularly potassium, sodium, and magnesium) periodically, especially during initial therapy or after dosage adjustments. Assess renal function and blood pressure regularly. Use caution in patients with impaired hepatic function or history of gout, as hydrochlorothiazide may exacerbate these conditions. Photosensitivity reactions may occur; advise sun protection. Pregnancy Category B: use only if clearly needed. Not recommended during breastfeeding.

Contraindications

Hypersensitivity to hydrochlorothiazide or other sulfonamide-derived drugs. Anuria. Concomitant use with aliskiren in patients with diabetes. Severe renal impairment (eGFR <30 mL/min). Refractory hypokalemia or hypercalcemia.

Possible side effect

Common: hypokalemia, hyperuricemia, hyperglycemia, dizziness, headache, orthostatic hypotension. Less common: hyponatremia, hypomagnesemia, hypercalcemia, photosensitivity, rash, impotence. Rare: pancreatitis, jaundice, leukopenia, agranulocytosis, aplastic anemia.

Drug interaction

Potentiates hypotensive effects of other antihypertensives. NSAIDs may reduce diuretic and antihypertensive efficacy. Increases risk of lithium toxicity. Corticosteroids and amphotericin B may enhance hypokalemia. Cholestyramine and colestipol reduce absorption. May enhance effects of neuromuscular blocking agents. Alcohol, barbiturates, or narcotics may potentiate orthostatic hypotension.

Missed dose

If a dose is missed, take it as soon as remembered unless it is nearly time for the next dose. Do not double the dose to catch up. Resume the regular dosing schedule.

Overdose

Symptoms include electrolyte imbalance (especially hypokalemia and hyponatremia), dehydration, hypotension, drowsiness, and GI disturbances. Management is supportive: replace fluid and electrolytes, monitor vital signs and renal function. Hemodialysis is not effective for hydrochlorothiazide removal.

Storage

Store at room temperature (20–25°C), away from light and moisture. Keep in the original container, tightly closed. Do not use after the expiration date. Keep out of reach of children and pets.

Disclaimer

This information is for educational purposes and does not replace professional medical advice, diagnosis, or treatment. Always consult a healthcare provider for personalized recommendations and before starting or changing any medication regimen.

Reviews

Hydrochlorothiazide is consistently rated as effective and tolerable in clinical settings, with many patients experiencing significant improvements in blood pressure control and fluid-related symptoms. Long-term user reviews often highlight its reliability, though some note the need for periodic electrolyte monitoring. Physician feedback underscores its value as a foundational therapy in hypertension management, particularly given its generic affordability and compatibility with combination regimens.