1. Introduction
Irbesartan is an angiotensin II receptor blocker (ARB) used to manage hypertension, diabetic nephropathy, and other cardiovascular conditions. By blocking angiotensin II receptors, it prevents vasoconstriction, reduces aldosterone secretion, and lowers blood pressure while protecting kidney function.
2. Indications
- Approved Indications:
- Hypertension (primary or essential hypertension).
- Diabetic nephropathy in type 2 diabetes with hypertension.
- Off-Label Uses:
- Heart failure (as part of combination therapy).
- Proteinuria (non-diabetic kidney disease).
3. Dosage
- Hypertension:
- Initial dose: 150 mg once daily.
- Maintenance dose: 150–300 mg once daily.
- Diabetic Nephropathy:
- 300 mg once daily (target dose).
- Elderly Patients:
- Start with 75 mg once daily if there are concerns about renal or hepatic function.
4. Administration
- Take orally once daily, with or without food.
- Consistent timing of doses is recommended for optimal blood pressure control.
5. Forms Available
- Tablets: 75 mg, 150 mg, 300 mg.
6. Side Effects
6.1. Common Side Effects
- Dizziness.
- Fatigue.
- Nausea or upset stomach.
- Hyperkalaemia (elevated potassium levels).
6.2. Less Common Side Effects
- Headache.
- Muscle pain (myalgia).
- Diarrhoea.
6.3. Rare but Serious Side Effects
- Hypotension (especially in volume-depleted patients).
- Kidney dysfunction or acute kidney injury.
- Angioedema (swelling of face, lips, or throat).
7. Warnings
- Hyperkalaemia: Monitor potassium levels, especially in patients with kidney impairment or those on potassium-sparing diuretics.
- Renal Function Impairment: Monitor kidney function in patients with pre-existing kidney disease or those on nephrotoxic medications.
- Angioedema: Discontinue immediately if swelling occurs.
8. Precautions
- Avoid use in:
- Severe renal impairment without monitoring.
- Severe hepatic impairment.
- Bilateral renal artery stenosis or solitary kidney.
- Use cautiously in patients with a history of hypotension or volume depletion (e.g., due to diuretics).
9. Interactions
- Drug-Drug Interactions:
- Potassium-sparing diuretics (e.g., spironolactone): Increased risk of hyperkalaemia.
- NSAIDs: May reduce the antihypertensive effect and worsen kidney function.
- Lithium: Increased risk of lithium toxicity.
- Drug-Food Interactions:
- No significant food interactions; can be taken with or without meals.
10. Monitoring Parameters
- Blood pressure (ensure effective reduction).
- Serum potassium levels (to avoid hyperkalaemia).
- Renal function tests (e.g., serum creatinine, eGFR).
- Signs of angioedema.
11. Use in Children
- Safety and efficacy have not been established in children under 18 years.
12. Use in Pregnancy
- Category D: Contraindicated during pregnancy. Can cause foetal toxicity, including renal failure, hypotension, and death.
13. Use in Elderly
- Safe with dose adjustments as needed based on renal function. Start at the lower end of the dosing range.
14. Use in Kidney Disease
- Dose adjustments are not usually necessary for mild to moderate renal impairment. Monitor closely in severe cases or in patients on diuretics.
15. Use in Liver Disease
- Use cautiously in mild to moderate liver impairment. Avoid in severe hepatic impairment due to limited safety data.
16. Patient Counselling Points
- Take irbesartan at the same time each day, with or without food.
- Do not stop taking the medication abruptly without consulting your doctor.
- Stay hydrated, but avoid potassium supplements or salt substitutes without medical advice.
- Report any swelling of the face, lips, tongue, or throat immediately, as this may indicate angioedema.
- Monitor your blood pressure regularly and attend follow-up appointments for blood tests.
17. Table of Brand Names, Manufacturers, and Prices
Brand Name | Manufacturer | Price (USD) |
---|---|---|
Avapro | Sanofi | $50–80 (30 tablets, 150 mg) |
Aprovel | Sanofi | $45–70 (30 tablets, 150 mg) |
Generic Irbesartan | Various manufacturers | $10–30 (30 tablets, 150 mg) |
18. FAQs (15 Questions)
- What is irbesartan used for?
It is used to treat hypertension and protect kidney function in type 2 diabetes. - How does irbesartan work?
It blocks angiotensin II receptors, reducing blood vessel constriction and lowering blood pressure. - How long does it take for irbesartan to start working?
Blood pressure reduction begins within 1–2 hours, but full effects may take 4–6 weeks. - What is the usual dose of irbesartan for hypertension?
The typical starting dose is 150 mg once daily, which can be increased to 300 mg if needed. - Can irbesartan cause side effects?
Yes, common side effects include dizziness, fatigue, and nausea. Rarely, it may cause kidney dysfunction or angioedema. - Is irbesartan safe in pregnancy?
No, it is contraindicated in pregnancy due to the risk of foetal harm. - Can irbesartan cause high potassium levels?
Yes, it can cause hyperkalaemia, especially in patients with kidney impairment or those taking potassium supplements. - What should I do if I miss a dose?
Take it as soon as you remember, but skip it if it’s close to the next dose. Do not double up. - Can I take irbesartan with other blood pressure medications?
Yes, but consult your doctor, especially if combining with diuretics or other ARBs/ACE inhibitors. - Does irbesartan interact with NSAIDs?
Yes, NSAIDs may reduce its effectiveness and increase the risk of kidney problems. - Is irbesartan safe for the elderly?
Yes, but doses should be adjusted based on kidney function. - Can irbesartan affect kidney function?
Rarely, it may reduce kidney function in susceptible individuals, especially those with pre-existing kidney disease. - How should irbesartan be stored?
Store at room temperature, away from moisture and heat. - Can I stop taking irbesartan if my blood pressure is normal?
No, continue taking it as prescribed to maintain blood pressure control. - Can irbesartan be used in children?
It is not typically recommended for children under 18 years.