From the Guidelines
Irbesartan is an angiotensin II receptor blocker (ARB) that should be prescribed at an initial dose of 150 mg once daily, with a maximum dose of 300 mg once daily for blood pressure control, as recommended by the most recent guidelines 1. The parameters of Irbesartan (Ang908) are as follows:
- Starting dose: 150 mg daily
- Goal dose: 150-300 mg daily, with the goal dose being at the higher end of the dose range when possible, as indicated in the KDOQI clinical practice guidelines 1
- Administration: can be taken with or without food
- Dosage adjustments: not typically required for elderly patients or those with mild to moderate hepatic impairment, though caution is advised in severe hepatic disease The medication works by blocking the binding of angiotensin II to its receptors, thereby preventing vasoconstriction and aldosterone secretion, which leads to decreased blood pressure. Some key points to consider when prescribing Irbesartan include:
- Common side effects: dizziness, fatigue, and hypotension, particularly when initiating therapy
- Contraindications: pregnancy due to potential fetal harm, and should not be used with aliskiren in patients with diabetes or renal impairment
- Monitoring: regular monitoring of blood pressure, renal function, and potassium levels is recommended during treatment, as suggested by the 2017 ACC/AHA/AAPA/ABC/ACPM/AGS/APhA/ASH/ASPC/NMA/PCNA guideline for the prevention, detection, evaluation, and management of high blood pressure in adults 1.
From the FDA Drug Label
The oral absorption of irbesartan is rapid and complete with an average absolute bioavailability of 60% to 80%. Following oral administration of irbesartan, peak plasma concentrations of irbesartan are attained at 1.5 to 2 hours after dosing. Irbesartan exhibits linear pharmacokinetics over the therapeutic dose range. Irbesartan is 90% bound to serum proteins (primarily albumin and α1-acid glycoprotein) with negligible binding to cellular components of blood. The average volume of distribution is 53 to 93 liters Total plasma and renal clearances are in the range of 157 to 176 mL/min and 3.0 to 3.5 mL/min, respectively. The terminal elimination half-life of irbesartan averages 11 to 15 hours. Steady-state concentrations are achieved within 3 days. Limited accumulation of irbesartan (<20%) is observed in plasma upon repeated once-daily dosing and is not clinically relevant.
The parameters of Irbesartan include:
- Bioavailability: 60% to 80%
- Peak plasma concentrations: 1.5 to 2 hours after dosing
- Volume of distribution: 53 to 93 liters
- Protein binding: 90% bound to serum proteins
- Clearance: 157 to 176 mL/min (total plasma) and 3.0 to 3.5 mL/min (renal)
- Half-life: 11 to 15 hours
- Steady-state concentrations: achieved within 3 days 2
From the Research
Parameters of Irbesartan (Ang908)
- Pharmacological Properties: Irbesartan is a potent and selective angiotensin II subtype 1 receptor antagonist 3, 4, 5.
- Dosage and Administration: The recommended starting dosage is 150 mg once daily, which can be increased to 300 mg 6.
- Antihypertensive Effect: Irbesartan produces dose-dependent blood pressure reductions, with 24-hour activity confirmed by ambulatory blood pressure monitoring 6.
- Efficacy: Irbesartan is effective in the elderly and non-elderly, men and women, and in cases of mild and severe hypertension 6.
- Combination Therapy: The antihypertensive efficacy of irbesartan is enhanced by the coadministration of hydrochlorothiazide 3, 4, 5, 7.
- Renoprotective Effects: Irbesartan has been shown to exert a renoprotective effect in hypertensive patients with type 2 diabetes at both the early and later stages of diabetic nephropathy 3, 4, 5, 7.
- Tolerability and Safety: Irbesartan is well tolerated, with an overall incidence of adverse events similar to that of placebo 3, 6.