Comparative Pharmacology
Head-to-head clinical analysis: CAPTOPRIL AND HYDROCHLOROTHIAZIDE versus METAHYDRIN.
Peer-Reviewed Evidence
Head-to-head clinical analysis: CAPTOPRIL AND HYDROCHLOROTHIAZIDE versus METAHYDRIN.
CAPTOPRIL AND HYDROCHLOROTHIAZIDE vs METAHYDRIN
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Captopril is an angiotensin-converting enzyme (ACE) inhibitor that inhibits the conversion of angiotensin I to angiotensin II, resulting in vasodilation and decreased aldosterone secretion. Hydrochlorothiazide is a thiazide diuretic that inhibits the Na+/Cl- cotransporter in the distal convoluted tubule, increasing excretion of sodium and water.
Metahydrin (trichlormethiazide) is a thiazide diuretic that inhibits the sodium-chloride symporter (NCC) in the distal convoluted tubule of the nephron, reducing sodium and chloride reabsorption and increasing excretion of water, sodium, chloride, and potassium.
1 tablet (captopril 25 mg / hydrochlorothiazide 15 mg) orally once daily, titrated up to a maximum of 1 tablet (captopril 50 mg / hydrochlorothiazide 25 mg) twice daily.
Oral, 50-100 mg once daily. Maximum 200 mg/day.
None Documented
None Documented
Captopril: ~2 hours (prolonged to 6-8 hours in heart failure or renal impairment). Hydrochlorothiazide: 5.6-14.8 hours (mean ~9.6 hours; prolonged in renal impairment).
18-30 hours (clinically relevant for once-daily dosing in hypertension; prolonged in renal impairment)
Captopril: renal (95%), primarily as unchanged drug and disulfide metabolites. Hydrochlorothiazide: renal (≥95%) as unchanged drug via tubular secretion.
Renal: 30% (fecal: 70% as unabsorbed drug, primarily biliary elimination; <1% unchanged in urine)
Category A/B
Category C
Thiazide Diuretic
Thiazide Diuretic