Irbesartan

What is Irbesartan?

Irbesartan is a prescription medication that belongs to a class of drugs called angiotensin receptor blockers (ARBs). It is primarily used to treat high blood pressure (hypertension) and to protect the kidneys in people with type 2 diabetes. This medication helps relax blood vessels, making it easier for the heart to pump blood throughout the body.

Uses

Irbesartan is approved for several cardiovascular and kidney-related conditions:

• Hypertension: The primary use is treating high blood pressure in adults and children over 6 years old, helping to reduce the risk of heart attack, stroke, and kidney problems
• Diabetic nephropathy: Protects kidney function in people with type 2 diabetes and high blood pressure, slowing the progression of kidney disease
• Heart failure: Sometimes prescribed as part of combination therapy to help manage heart failure when other medications are not suitable
• Cardiovascular risk reduction: May be used in patients at high risk for heart disease to help prevent cardiovascular events
• Chronic kidney disease: Can help slow the progression of kidney disease in certain patients, even those without diabetes

How it works

Irbesartan works by blocking angiotensin II receptors in blood vessels and other tissues. Angiotensin II is a hormone that causes blood vessels to narrow and triggers the release of another hormone that increases blood pressure. By blocking these receptors, irbesartan allows blood vessels to relax and widen, which lowers blood pressure and reduces the workload on the heart and kidneys.

Side effects

Common side effects include:

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• Dizziness or lightheadedness
• Fatigue or weakness
• Nausea
• Headache
• Diarrhea
• Heartburn
• Muscle or joint pain
• Upper respiratory tract infections

Serious side effects that require immediate medical attention:

• Severe dizziness or fainting
• Irregular heartbeat or chest pain
• Signs of kidney problems (changes in urination, swelling)
• High potassium levels (muscle weakness, irregular heartbeat)
• Severe allergic reactions (swelling of face, lips, throat, difficulty breathing)

Warnings and precautions

• Pregnancy: Irbesartan can cause serious harm or death to an unborn baby, especially during the second and third trimesters. Women should inform their doctor immediately if they become pregnant while taking this medication.
• Kidney function: Patients with severe kidney disease or those on dialysis should use this medication with extreme caution, as it can worsen kidney function in some cases.
• Liver impairment: People with liver problems may need dosage adjustments, as the medication is processed by the liver.
• Volume depletion: Patients who are dehydrated or taking diuretics may experience severe drops in blood pressure when starting irbesartan.
• Surgery: Patients should inform their surgeon and anesthesiologist about taking irbesartan before any surgical procedures, as it can affect blood pressure during anesthesia.

Interactions

• ACE inhibitors: Combining with drugs like lisinopril can increase the risk of kidney problems and high potassium levels
• Potassium supplements or salt substitutes: Can lead to dangerously high potassium levels in the blood
• NSAIDs: Pain relievers like ibuprofen and naproxen can reduce irbesartan’s effectiveness and increase kidney damage risk
• Lithium: Irbesartan can increase lithium levels in the blood, potentially leading to toxicity
• Diuretics: Water pills can enhance blood pressure-lowering effects, potentially causing excessive drops in blood pressure
• Diabetes medications: May enhance blood sugar-lowering effects, requiring closer monitoring of blood glucose levels
• Warfarin: May alter blood clotting effects, requiring more frequent monitoring of clotting times
• Aliskiren: Should not be combined in patients with diabetes or kidney problems due to increased risk of complications

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Dosage

For adults with hypertension, the typical starting dose is 150 mg once daily, which may be increased to 300 mg daily if needed for optimal blood pressure control. For diabetic nephropathy, the usual dose is 300 mg once daily. Children aged 6-12 years typically start with 75 mg daily, while adolescents 13-16 years usually begin with 150 mg daily. Irbesartan can be taken with or without food, preferably at the same time each day. Dosage adjustments may be necessary for patients with kidney or liver problems, and all dosing decisions should be made by a qualified healthcare provider based on individual patient factors and response to treatment.

Sources: FDA DailyMed drug labels (public domain), BNF, WHO Essential Medicines List. This article is for informational purposes only and does not constitute medical advice. Always consult your healthcare provider before starting or stopping any medication.

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