Comparative Pharmacology
Head-to-head clinical analysis: HYDRALAZINE HYDROCHLORIDE AND HYDROCHLOROTHIAZIDE versus ZIDE.
Peer-Reviewed Evidence
Head-to-head clinical analysis: HYDRALAZINE HYDROCHLORIDE AND HYDROCHLOROTHIAZIDE versus ZIDE.
HYDRALAZINE HYDROCHLORIDE AND HYDROCHLOROTHIAZIDE vs ZIDE
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Hydralazine is a direct-acting arteriolar vasodilator that reduces peripheral vascular resistance via relaxation of vascular smooth muscle, possibly by interfering with calcium transport. Hydrochlorothiazide is a thiazide diuretic that inhibits the sodium-chloride symporter in the distal convoluted tubule, increasing excretion of sodium and water, and reducing plasma volume.
Hydrochlorothiazide is a thiazide diuretic that inhibits the sodium-chloride symporter in the distal convoluted tubule of the nephron, reducing reabsorption of sodium and chloride and increasing excretion of water, sodium, chloride, potassium, and bicarbonate.
Initially one capsule (25 mg hydralazine/25 mg hydrochlorothiazide, or 50 mg hydralazine/50 mg hydrochlorothiazide) twice daily, increase as needed to a maximum of 200 mg hydralazine/200 mg hydrochlorothiazide daily.
10 mg orally once daily.
None Documented
None Documented
Clinical Note
moderateBendroflumethiazide + Digoxin
"The risk or severity of adverse effects can be increased when Bendroflumethiazide is combined with Digoxin."
Clinical Note
moderateMethyclothiazide + Digoxin
"The risk or severity of adverse effects can be increased when Methyclothiazide is combined with Digoxin."
Clinical Note
moderateHydrochlorothiazide + Digoxin
"The risk or severity of adverse effects can be increased when Hydrochlorothiazide is combined with Digoxin."
Clinical Note
moderateHydralazine: 2-8 hours (terminal, prolonged in renal impairment; acetylator phenotype affects clearance; slow acetylators have 2-fold longer half-life). Hydrochlorothiazide: 6-15 hours (terminal, prolonged in renal impairment; clinically relevant for once-daily dosing).
6-8 hours in normal renal function; prolonged to 20-40 hours in severe renal impairment (eGFR <30 mL/min).
Hydralazine: 90% renal (primarily as metabolites, 10-15% unchanged); Hydrochlorothiazide: >95% renal (unchanged). Biliary/fecal: negligible for both.
Renal: 70% unchanged; Biliary/fecal: 30% (as metabolites and parent compound).
Category A/B
Category C
Thiazide Diuretic
Thiazide Diuretic
Hydroflumethiazide + Digoxin
"The risk or severity of adverse effects can be increased when Hydroflumethiazide is combined with Digoxin."