Indications
Irbesartan is used to treat high blood pressure in adults. It is also used to protect the kidneys in people with type 2 diabetes who have high blood pressure and early kidney disease. It is available alone and in combination with Hydrochlorothiazide or Amlodipine.
How It Works
Irbesartan is an angiotensin II receptor blocker (ARB). It blocks the action of angiotensin II, a natural substance that tightens blood vessels. As a result, the blood vessels relax, blood pressure falls and the kidneys are under less strain.
Dosage and Administration
- High blood pressure: usually 150 mg once a day. The doctor may increase it to 300 mg once a day if needed.
- People over 75 years or on dialysis: the doctor may start with 75 mg once a day.
- Kidney disease in type 2 diabetes: usually started at 150 mg once a day and increased to 300 mg once a day.
- Children: not usually recommended; only as prescribed.
Take at the same time each day, with or without food. The full effect on blood pressure takes about 4 to 6 weeks. Keep taking it even if you feel well.
Interactions
Potassium supplements, salt substitutes that contain potassium, and medicines such as Spironolactone, Amiloride, Trimethoprim and Heparin can raise blood potassium too much. Using it with an ACE inhibitor (such as Enalapril or Ramipril) or Aliskiren increases the risk of kidney problems and high potassium. Painkillers such as Ibuprofen and Diclofenac can weaken its effect and harm the kidneys. It can raise Lithium levels. Other blood pressure medicines add to its effect.
Contraindications
- Pregnancy.
- Allergy to irbesartan or any ingredient.
- Use together with Aliskiren in people with diabetes or reduced kidney function.
Side Effects
Common: dizziness, especially when standing up, tiredness, nausea, raised blood potassium and muscle or joint pain. Less common: cough, diarrhoea, indigestion, flushing and sexual problems.
Get urgent medical help if you have swelling of the face, lips, tongue or throat, fainting, passing very little urine, muscle weakness or an irregular heartbeat (which can be signs of high potassium), or yellowing of the skin or eyes.
Pregnancy and Lactation
Do not take irbesartan in pregnancy, as it can harm the baby’s kidneys and growth, especially after the first 3 months. If you become pregnant, contact your doctor straight away to switch to another medicine. It is not recommended while breastfeeding; your doctor will choose a better-studied alternative.
Precautions and Warnings
Blood pressure may drop too much if you are dehydrated from vomiting, diarrhoea or water tablets, so tell your doctor. Use with care in kidney disease, narrowing of the kidney arteries, liver disease, heart valve narrowing and after a kidney transplant. Your doctor may check kidney function and potassium with blood tests. Dizziness can affect driving, especially at the start.
Overdose
An overdose can cause very low blood pressure, dizziness and a fast or slow heartbeat. Lie down with the legs raised and seek medical help straight away.
Therapeutic Class
Angiotensin II receptor blocker (ARB).
Storage
Store below 30°C in a dry place, away from light and out of the reach of children.
Prepared by the Oshud Alo team from standard drug references. For information only; always follow your doctor's advice.