Comparative Pharmacology
Head-to-head clinical analysis: CHLOROTHIAZIDE versus HYDRALAZINE HYDROCHLORIDE AND HYDROCHLOROTHIAZIDE.
Peer-Reviewed Evidence
Head-to-head clinical analysis: CHLOROTHIAZIDE versus HYDRALAZINE HYDROCHLORIDE AND HYDROCHLOROTHIAZIDE.
CHLOROTHIAZIDE vs HYDRALAZINE HYDROCHLORIDE AND HYDROCHLOROTHIAZIDE
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Chlorothiazide inhibits the Na+-Cl- symporter in the distal convoluted tubule, reducing sodium and chloride reabsorption and promoting diuresis. It also causes vasodilation by reducing peripheral vascular resistance.
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.
500 mg to 1000 mg orally or intravenously once or twice daily.
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.
None Documented
None Documented
Clinical Note
moderateHydrochlorothiazide + Digoxin
"The risk or severity of adverse effects can be increased when Hydrochlorothiazide is combined with Digoxin."
Clinical Note
moderateChlorothiazide + Digoxin
"The risk or severity of adverse effects can be increased when Chlorothiazide is combined with Digoxin."
Clinical Note
moderateHydrochlorothiazide + Digitoxin
"The risk or severity of adverse effects can be increased when Hydrochlorothiazide is combined with Digitoxin."
Clinical Note
moderateTerminal half-life: 45–120 minutes (prolonged in renal impairment); clinical context: short duration requires frequent dosing
Hydralazine: 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).
Renal: ~95% (tubular secretion); Fecal: <5%
Hydralazine: 90% renal (primarily as metabolites, 10-15% unchanged); Hydrochlorothiazide: >95% renal (unchanged). Biliary/fecal: negligible for both.
Category C
Category A/B
Thiazide Diuretic
Thiazide Diuretic
Chlorothiazide + Digitoxin
"The risk or severity of adverse effects can be increased when Chlorothiazide is combined with Digitoxin."