Irbes

• Essential (primary) hypertension — used as monotherapy or in combination with other antihypertensive agents for blood pressure control.
• Diabetic nephropathy with proteinuria (type 2 diabetes mellitus) — indicated to reduce the progression of nephropathy in hypertensive type 2 diabetic patients, slowing albuminuria and renal function decline.
• Clinically accepted off-label use — as part of cardiovascular risk reduction strategies and in management of left ventricular hypertrophy where an ARB is considered appropriate.

Adults (hypertension)

• Initial dose: 150 mg once daily.
• Maintenance: 150–300 mg once daily; maximum dose 300 mg once daily.

Type 2 diabetic patients with nephropathy

• Start with 150 mg once daily; titrate to 300 mg once daily as preferred for renal benefit.

Elderly

• No routine dose adjustment solely for age; titrate carefully with close monitoring.

Pediatrics

• Use only if approved in local guidelines; dosing should be weight-based and under specialist supervision.

Renal impairment

• No adjustment required for mild-to-moderate impairment; use caution in severe impairment and avoid in bilateral renal artery stenosis.

Hepatic impairment

• Use with caution in significant hepatic dysfunction; consider lower starting doses.

Administration

• Oral route; once daily at the same time each day.
• May be taken with or without food.

Irbesartan selectively blocks the angiotensin II type-1 (AT₁) receptor in vascular smooth muscle and the adrenal gland. This inhibits angiotensin II–mediated vasoconstriction, aldosterone release, sympathetic activation, and sodium/water retention. The result is reduced vascular resistance, lowered blood pressure, and decreased intraglomerular pressure, which slows renal damage progression in diabetic nephropathy.

• Absorption: Rapid and nearly complete, with peak plasma concentration in ~1.5–2 hours. Bioavailability ~60–80%. Food has minimal effect.
• Distribution: Extensively protein-bound; moderate volume of distribution.
• Metabolism: Minimal hepatic metabolism, mainly via CYP2C9; no clinically important active metabolites.
• Elimination: Half-life ~11–15 hours. Excreted ~20% in urine, ~80% in feces; <2% unchanged in urine.
• Steady state: Achieved within ~3 days of once-daily dosing.

• Pregnancy: Contraindicated in the 2nd and 3rd trimesters due to risk of fetal harm (renal failure, oligohydramnios, skull hypoplasia, fetal death). Discontinue immediately if pregnancy occurs.
• Lactation: Unknown if excreted in human milk; avoid use or discontinue breastfeeding due to potential risk to infants.
• Note: Caution required during the 1st trimester; alternative agents are preferred.

• Class: Angiotensin II receptor blocker (ARB)
• Subclass: Selective AT₁ receptor antagonist

• Hypersensitivity to irbesartan or any formulation component.
• Pregnancy (especially 2nd and 3rd trimesters).
• Concomitant use with aliskiren in patients with diabetes.

• Risk of fetal harm — discontinue if pregnancy detected.
• May cause renal impairment in patients with bilateral renal artery stenosis or severe renal disease — monitor renal function.
• Risk of hyperkalemia — monitor potassium levels, especially with potassium supplements or potassium-sparing diuretics.
• Symptomatic hypotension may occur, particularly in volume-depleted patients.
• Avoid dual renin-angiotensin system blockade (e.g., with ACE inhibitors or other ARBs).

Common:

• Dizziness, headache, fatigue.
• Upper respiratory tract infections.
• Nausea, diarrhea.

Less common:

• Orthostatic hypotension.
• Myalgia, back pain.

Serious/Rare:

• Acute renal failure.
• Severe hyperkalemia.
• Hypersensitivity reactions (angioedema very rare).

• Potassium supplements/potassium-sparing diuretics — increased risk of hyperkalemia.
• NSAIDs — may reduce antihypertensive effect and worsen renal function.
• Lithium — increased risk of lithium toxicity; monitor levels.
• Dual RAAS blockade with ACE inhibitors or aliskiren — increased risk of hypotension, hyperkalemia, and renal dysfunction.
• CYP2C9 inhibitors/inducers — may affect irbesartan levels, though clinically significant changes are uncommon.

• Strengthened pregnancy warnings with emphasis on discontinuation upon detection.
• Continued recommendation against dual RAAS blockade due to adverse outcome risks.
• In diabetic nephropathy, 300 mg daily confirmed as the dose providing renal protective benefits.

• Store at 20°C–25°C; excursions permitted between 15°C–30°C.
• Protect from light and moisture.
• Keep in original container and out of reach of children.
• No refrigeration or reconstitution required.