Hydrochlorothiazide

The tablet label covers hypertension alone or with other antihypertensives, and adjunctive edema treatment associated with heart failure, cirrhosis, corticosteroid/estrogen therapy or renal disorders. The selected 12.5 mg capsule label is for hypertension.

Routine diuresis in a healthy pregnancy is inappropriate; hydrochlorothiazide does not prevent or treat preeclampsia. Physiologic dependent edema is generally managed without diuretics. Pathologic edema requires an individualized clinical assessment.

Tablet label: 1–2 mg/kg/day in one or two doses; maximum 37.5 mg/day up to age 2 and 100 mg/day at ages 2–12. Infants under 6 months may require up to 3 mg/kg/day in two doses under specialist supervision. Pediatric evidence is empiric/published experience, without well-controlled trials. Capsule safety and effectiveness in children are not established.

Anuria is contraindicated. Severe renal disease warrants caution because azotemia and accumulation can occur; consider withholding or stopping for progressive renal impairment. No fixed creatinine-clearance adjustment table is supplied by these labels. In hepatic impairment, even small fluid/electrolyte shifts can precipitate coma; individualize carefully.

Use the prescribed tablet strength or 12.5 mg capsule. Combination antihypertensive products contain additional ingredients and have separate labels. Do not infer that capsule pediatric restrictions or tablet edema doses are interchangeable.

Anuria, or hypersensitivity to hydrochlorothiazide/product ingredients or other sulfonamide-derived drugs as stated in the selected labels. Evaluate the exact allergy history before treatment.

Neither selected single-ingredient oral label carries a boxed warning. Serious electrolyte and ocular warnings still apply.

Dizziness, orthostatic hypotension, GI symptoms, muscle cramps, photosensitivity and metabolic changes are reported; serious reactions include severe skin reactions, pancreatitis, blood dyscrasias and renal injury. Current labels associate cumulative exposure with non-melanoma skin cancer, especially squamous-cell cancer in White patients at high cumulative doses. Protect skin and arrange screening; individualize benefit–risk assessment rather than stopping routine therapy without a plan. Overdose causes dehydration and electrolyte depletion and requires urgent clinical assessment and supportive correction.

• Lithium: generally avoid; renal clearance falls and toxicity risk rises.
• Digoxin: hypokalemia can increase cardiac toxicity; assess electrolytes and clinical risk.
• NSAIDs may blunt natriuresis, diuresis and BP lowering; monitor response.
• Other antihypertensives, alcohol, opioids and barbiturates can increase hypotension.
• Corticosteroids or ACTH increase electrolyte loss, especially potassium.
• Insulin/oral diabetes medicines may need adjustment if glucose rises.
• Cholestyramine/colestipol reduce absorption; coordinate administration with the pharmacist.
• Nondepolarizing muscle relaxants may have enhanced effects; inform the perioperative team. Pressor response may decrease without precluding use.
• Stop as directed before parathyroid-function testing because calcium handling is altered.

Use only when clearly needed after clinical review. Thiazides cross the placenta; neonatal jaundice, thrombocytopenia and adult-type adverse effects are possible. Do not use routinely for normal pregnancy edema.

Labels advise a decision between nursing and treatment because the drug enters milk. LactMed considers doses up to 50 mg/day acceptable during breastfeeding; intense diuresis at larger doses may reduce milk production. Consider maternal need, dose, milk supply and infant health with the clinician.

Tablet pediatric directions are based on experience rather than controlled trials; the capsule label states pediatric safety/effectiveness are unestablished. The capsule label recommends a 12.5 mg start in older adults, with 12.5 mg increments if needed, because BP reduction and adverse effects may be greater.

Hydrochlorothiazide reduces renal sodium/chloride reabsorption, increasing water excretion with possible potassium and magnesium loss. Diuresis starts around 2 hours, peaks around 4 hours and lasts 6–12 hours. Its precise antihypertensive mechanism is not established.

Metabolism

Not metabolized.

Elimination

Predominantly renal; at least 61% of an oral dose eliminated unchanged within 24 hours in tablet-label data.

Half-life

5.6–14.8 hours in tablet-label studies; renal impairment prolongs elimination.

Distribution

Crosses the placenta and enters breast milk.

• Follow BP response, orthostatic symptoms, edema/weight and hydration.
• Check electrolytes and renal function periodically; reassess promptly with vomiting, diarrhea, heavy diuresis or reduced intake.
• Assess glucose with diabetes, uric acid/gout when clinically relevant, and calcium if elevated or parathyroid disease is suspected.
• Arrange regular skin cancer screening and examine new or changing lesions.

• Take only the prescribed product and dose; consult before using NSAIDs or changing potassium intake/supplements.
• Report weakness, cramps, confusion, fainting, markedly reduced urine or persistent vomiting.
• Seek urgent care for new eye pain or sudden blurred vision.
• Use sun protection and report new, persistent or changing skin lesions.

Label packager

Golden State Medical Supply; manufactured by Leading Pharma.

Appearance / imprint

Peach round bisected tablet; EP above score, 131 below.

Example NDC

51407-331-01 · 100 tablets.

U.S. status

Prescription; ANDA product.

Selected tablets

12.5, 25 and 50 mg.

Selected capsule

12.5 mg; light blue SG / 146; Westminster NDC 69367-219-01, 100 capsules.

Combination products

Separate ingredient, strength and safety checks required.

Selected tablets: 20–25°C in a well-closed child-resistant container. Capsules: 20–25°C in a tight light-resistant container, protected from moisture and freezing. Keep out of children’s reach.