Irbesartan

BRAND NAMES:

Avalide -  Avalide is a drug composition of irbesartan hydrochlorothiazide tablets 150/2.5 or 300/2.5mg available in the market in the treatment of hypertension.

Avapro – It consists of the main active ingredient irbesartan and is available in the market as Avapro irbesartan 150/300mg tablets.

Ifirmacombi- It is a combination of two active ingredients irbesartan and hydrochlorothiazide. It is available in the form of Ifirmacombi 300mg/25mg film-coated tablets.

Karvea – Irbesartan is the main active ingredient in the Karvea in the form of tablets strength (75,150 and 300mg).

Karvezide – These are available in the form of tablets which are combination of irbesartan and hydrochlorothiazide as active ingredients with strengths 150 mg or 300 mg irbesartan and 2.5mg hydrochlorothiazide ; 300mg irbesartan and 25 mg hydrochlorothiazide.

MECHANISM OF ACTION:

Irbesartan is an oral drug used to treat excessive blood pressure and diabetic nephropathy. It is an angiotensin receptor blocker, like valsartan, losartan, and candesartan. Angiotensin, produced in the blood by the activity of angiotensin-converting enzyme, is a potent molecule that binds to angiotensin receptors present in a variety of tissues, but principally on smooth muscle cells in blood arteries. Angiotensin binds to receptors, causing blood vessels to constrict, resulting in increased blood pressure. Irbesartan inhibits the angiotensin receptor. Irbesartan lowers blood pressure by inhibiting the effect of angiotensin.

PHARMACOKINETICS:

Absorption: In oral administration, irbesartan is rapidly and well absorbed. The average absolute oral bioavailability of irbesartan was 60-80%. Median peak plasma concentrations generally occurred 1.5-2 hours after oral administration of irbesartan capsules and tablets. Food did not affect the bioavailability.

Distribution: Irbesartan is 90% protein-bound in plasma and has little binding to blood cell components. The amount of distribution is 53-93 liters.

Metabolism: Whether administered orally or intravenously, unaltered irbesartan accounted for more than 80% of circulating plasma radioactivity. Irbesartan is metabolized by the liver by glucuronide conjugation and oxidation. Irbesartan glucuronide is the most common metabolite in circulation. Irbesartan is largely oxidized by the cytochrome P450 isoenzyme CYP2C9, with CYP3A4 having little effect. It is not metabolized by most drug metabolism isoenzymes and does not stimulate or inhibit them. Irbesartan does not activate or inhibit the isoenzyme CYP3A4. 

Excretion: Urine excretes 20% of a radiolabelled oral dose of irbesartan, whereas stool excretes the remainder.

PHARMACODYNAMICS:

Irbesartan is an angiotensin receptor blocker prescribed to treat hypertension and diabetic nephropathy. It has a lengthy duration of effect because it is typically given once daily and a broad therapeutic index because dosages as low as 150 mg daily can be tolerated, but doses of 900 mg/day have been successfully tolerated in healthy human subjects. 

DOSAGE AND ADMINISTRATION: 

Irbesartan is available as Avapro in the oral dose forms listed below. 

The tablets' strengths are 75mg, 150mg, and 300mg. Irbesartan can be given orally, with or without food. If you miss a dose, do not take two doses at once. 

CONTRAINDICATIONS:

Irbesartan medicine is not recommended for patients who are hypersensitive to irbesartan or any other component of the irbesartan medication formulation. Do not combine irbesartan and aliskiren-containing medications in individuals with diabetes or moderate to severe renal impairment. In individuals with diabetic nephropathy, do not combine irbesartan and ACE inhibitors. 

DRUG INTERACTIONS:

• Combining irbesartan with potassium-sparing diuretics (spironolactone, triamterene). 

• Potassium supplementation may cause hyperkalemia and toxicity. 

• Combining irbesartan or other ARBs with nonsteroidal anti-inflammatory medications in individuals who are elderly, fluid-depleted, or have poor kidney function may result in impaired kidney function, including renal failure. These effects are usually reversible. There have been reports that aspirin and other NSAIDs, such as ibuprofen, indomethacin, and naproxen, may lessen the effects of ARBs. 

SIDE EFFECTS: 

Side effects of irbesartan include: 

• Reduced amount of urine passed. 

• Confusion, dizziness, lightheadedness. 

• Difficulty breathing; throat tightness 

• irregular or rapid heartbeat 

• Swelling of the cheeks, lips, tongue, hands, or feet. 

OVERDOSE:

Adults subjected to dosages of up to 900 mg/day for 8 weeks showed no harm. If the dose is exceeded, it causes some side effects. Symptoms may include dizziness, fainting, and rapid or sluggish heartbeat. 

TOXICITY:

The signs of an overdose include hypotension, tachycardia, or bradycardia. Terlipressin may treat hypotension and tachycardia when traditional vasopressors fail to control blood pressure.

STORAGE:

Should be stored at room temperature, between 68℉ and 77℉ (20℃ and 25°C). It can withstand temperatures ranging from 59℉ to 86℉ degrees (15℃ to 30℃) for brief periods, such as when transporting it. Store in a cool, dry place.