Comparative Pharmacology
Head-to-head clinical analysis: AVALIDE versus LOSARTAN POTASSIUM AND HYDROCHLOROTHIAZIDE.
Peer-Reviewed Evidence
Head-to-head clinical analysis: AVALIDE versus LOSARTAN POTASSIUM AND HYDROCHLOROTHIAZIDE.
AVALIDE vs LOSARTAN POTASSIUM AND HYDROCHLOROTHIAZIDE
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.
Losartan is an angiotensin II receptor blocker (ARB) that selectively antagonizes AT1 receptors, blocking vasoconstriction and aldosterone secretion. Hydrochlorothiazide is a thiazide diuretic inhibiting sodium and chloride reabsorption in the distal convoluted tubule, reducing plasma volume and peripheral resistance.
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.
Initial: losartan 50 mg/hydrochlorothiazide 12.5 mg orally once daily. Titrate to maximum losartan 100 mg/hydrochlorothiazide 25 mg once daily. Usual maintenance: losartan 50-100 mg/hydrochlorothiazide 12.5-25 mg 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.
Losartan: 2 hours; Active metabolite E-3174: 6-9 hours. Hydrochlorothiazide: 6-15 hours (mean 10 hours) with prolonged elimination in renal impairment.
Renal: HCTZ ~70% unchanged; Irbesartan ~20% unchanged, remainder as metabolites via biliary (60%) and renal (20%). Combined: Renal ~50%, biliary/fecal ~50%.
Losartan: 35% renal, 60% biliary/fecal; Hydrochlorothiazide: >95% renal (tubular secretion).
Category C
Category D/X
ARB and Thiazide Diuretic Combination
ARB