Comparative Pharmacology
Head-to-head clinical analysis: AVALIDE versus HYDROPRES 50.
Peer-Reviewed Evidence
Head-to-head clinical analysis: AVALIDE versus HYDROPRES 50.
AVALIDE vs HYDROPRES 50
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Avalide is a combination of an angiotensin II receptor blocker (irbesartan) and a thiazide diuretic (hydrochlorothiazide). Irbesartan blocks the vasoconstrictor and aldosterone-secreting effects of angiotensin II by selectively antagonizing the AT1 receptor. Hydrochlorothiazide increases sodium and water excretion by inhibiting the Na+/Cl- symporter in the distal convoluted tubule.
Hydrochlorothiazide is a thiazide diuretic that inhibits the sodium-chloride cotransporter in the distal convoluted tubule, increasing excretion of sodium, chloride, and water. Reserpine is a rauwolfia alkaloid that depletes catecholamines and serotonin from central and peripheral nerve endings, reducing sympathetic outflow and lowering blood pressure. The combination provides additive antihypertensive effect.
AVALIDE (irbesartan/hydrochlorothiazide) is available as tablets containing 150/12.5 mg, 300/12.5 mg, or 300/25 mg. The typical starting dose is 150/12.5 mg once daily, titrated to 300/12.5 mg once daily as needed. Maximum dose is 300/25 mg once daily.
HYDROPRES 50 is a fixed-dose combination of hydrochlorothiazide 50 mg and reserpine 0.125 mg. Usual adult dose: one tablet orally once daily.
None Documented
None Documented
Irbesartan: 11-15 h (terminal), HCTZ: 6-15 h (terminal). Clinical context: Steady state reached in 3-5 days; allows once-daily dosing.
Hydrochlorothiazide: 6-15 hr (terminal); Reserpine: 50-100 hr (terminal, biphasic). Clinical: HCTZ half-life prolonged in renal impairment; reserpine accumulates with repetitive dosing.
Renal: HCTZ ~70% unchanged; Irbesartan ~20% unchanged, remainder as metabolites via biliary (60%) and renal (20%). Combined: Renal ~50%, biliary/fecal ~50%.
Hydrochlorothiazide: 95% renal (65% unchanged); Reserpine: 30% renal, 60% fecal
Category C
Category C
ARB and Thiazide Diuretic Combination
Thiazide Diuretic Combination