Comparative Pharmacology
Head-to-head clinical analysis: HYDRALAZINE AND HYDROCHLOROTHIAZIDE versus METAHYDRIN.
Peer-Reviewed Evidence
Head-to-head clinical analysis: HYDRALAZINE AND HYDROCHLOROTHIAZIDE versus METAHYDRIN.
HYDRALAZINE AND HYDROCHLOROTHIAZIDE vs METAHYDRIN
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Hydralazine is a direct-acting smooth muscle vasodilator that relaxes arterioles, reducing peripheral resistance. Hydrochlorothiazide is a thiazide diuretic that inhibits the sodium-chloride symporter 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.
Oral: 1 tablet (hydralazine 25 mg / hydrochlorothiazide 25 mg) 1-2 times daily. Maximum: hydralazine 200 mg/day, hydrochlorothiazide 50 mg/day.
Oral, 50-100 mg once daily. Maximum 200 mg/day.
None Documented
None Documented
Hydralazine: 2-4 hours (fast acetylators), 4-8 hours (slow acetylators); extended in renal impairment. Hydrochlorothiazide: 6-15 hours; prolonged in renal impairment.
18-30 hours (clinically relevant for once-daily dosing in hypertension; prolonged in renal impairment)
Hydralazine: 80-90% renal (mostly as metabolites), <10% unchanged. Hydrochlorothiazide: 95-99% renal (unchanged).
Renal: 30% (fecal: 70% as unabsorbed drug, primarily biliary elimination; <1% unchanged in urine)
Category A/B
Category C
Thiazide Diuretic
Thiazide Diuretic