Irbesartan

What is irbesartan?

Irbesartan is a prescription-only medicine used to treat high blood pressure (hypertension) and to help protect kidney function in people with type 2 diabetes. It belongs to a group of drugs called angiotensin II receptor blockers (ARBs). Irbesartan is available in tablets under brand names such as Aprovel and CoAprovel (which combines irbesartan with a diuretic called hydrochlorothiazide)[1]. 

What is irbesartan used for?

Irbesartan is commonly prescribed to treat the following conditions[1]: 

• High blood pressure (hypertension), to reduce the risk of strokes, heart attacks, and kidney problems 

• Kidney damage in people with type 2 diabetes, especially where protein is found in the urine (an early sign of kidney impairment) 

How does irbesartan work?

Irbesartan works by blocking the action of angiotensin II, a chemical in the body that causes blood vessels to narrow. By blocking this effect, irbesartan[1]: 

• Relaxes and widens blood vessels 

• Lowers blood pressure 

• Improves blood flow 

• Reduces strain on the heart and kidneys 

Who can take irbesartan?

Irbesartan is generally suitable for most adults. It may be prescribed if you’ve taken other medicines to lower your blood pressure called angiotensin converting enzyme (ACE) inhibitors in the past. However, speak to a doctor or pharmacist first if you[1]: 

• Are allergic to irbesartan or any of its ingredients 

• Are pregnant, trying to get pregnant, or breastfeeding 

• Have severe heart, kidney, or liver problems 

• Have diabetes 

• Have recently had a kidney transplant 

• Have or recently had diarrhoea and vomiting 

• Are on a low-salt diet 

• Are taking aliskiren alongside diabetes or kidney disease 

Please tell your doctor or pharmacist about any conditions you may have or medication you take before you start treatment, and always follow the instructions in the Patient Information Leaflet[2].  

How do you take irbesartan?

Irbesartan should be taken exactly as directed. Take once a day, at the same time each day. It can be taken with or without food – swallow the tablet whole with water[1]. 

What is the typical dosage of irbesartan?

The dose may vary depending on your medical condition and response to treatment[1]: 

• Usual starting dose: 150mg once daily 

• Maintenance dose: 150-300mg once daily 

• For people with diabetic kidney disease: often 300mg once daily 

After a few weeks, your doctor will check your blood pressure and see if you have experienced any side effects. You may also need to have a blood test to check how well your kidneys are working and the potassium levels in your blood. They can then decide whether to change your dose or not[1]. 

Always take the dose prescribed by your doctor or pharmacist and follow the instructions on the label. 

Can you stop taking irbesartan?

Do not stop taking irbesartan without speaking to your doctor or pharmacist. Stopping treatment may cause your blood pressure to rise again, which increases your risk of complications such as heart attack or stroke[1]. 

What do you do if you take too much irbesartan?

Taking too much irbesartan can lead to dizziness or light-headedness and the possibility of fainting due to low blood pressure. Seek medical attention immediately or call NHS 111 if you think you have taken too much[1]. 

What do you do if you forget to take irbesartan?

If you forget a dose[1]: 

• Take it as soon as you remember 

• If it’s nearly time for your next dose, skip the missed one 

• Do not take two doses at the same time to make up for a missed dose  

What medicines can’t you take with irbesartan?

Some medicines may interact with irbesartan. Tell your doctor or pharmacist if you are taking[1]: 

• Other blood pressure medications, especially aliskiren or ACE inhibitors 

• Diuretics (water tablets) 

• Lithium, used for some mental health conditions 

• NSAIDs (such as ibuprofen), which may reduce kidney function 

• Potassium supplements or potassium-containing salt substitutes 

Always inform your doctor or pharmacist about all medications and supplements you take before you start a new medicine, and follow the instructions in the Patient Information Leaflet[2]. 

What are the side effects of irbesartan?

Like all medicines, irbesartan can cause side effects. Most are mild, but some may require medical attention. The most common side effects include[1]: 

• Dizziness or light-headedness 

• Nausea or vomiting 

• Fatigue 

• Muscle cramps or joint pain 

• Low blood pressure 

Serious but rare side effects include[1]: 

• Kidney problems (e.g., reduced urine output, swelling) or signs of a blood or bone marrow disorder (e.g., unusual bruising, persistent sore throat) 

• High potassium levels, which can cause an irregular heartbeat 

• symptoms of liver problems (e.g., yellowing of the skin or eyes, dark urine) 

You should contact your GP if you experience any of these symptoms. In rare cases, the medicine may cause a serious allergic reaction (anaphylaxis). You should call 999 or visit A&E immediately if you believe this is happening[1]. 

Symptoms of anaphylaxis include[1]:  

• Difficulty breathing  

• Tightness in throat and chest  

• Swelling of the tongue or throat  

• Feeling faint or dizzy  

• Blue/grey skin or lips  

• Loss of consciousness 

If you experience any side effects, including those not listed, you are encouraged to report them via the Yellow Card Scheme or contact your doctor, pharmacist, or nurse. This information is intended as a summary for general awareness and does not replace professional medical advice. 

The information provided in the side effects section is not a comprehensive list of all possible side effects associated with this medication. For a complete list of side effects, please refer to the Patient Information Leaflet (PIL) provided with your medication or consult your healthcare professional[2]. 

Frequently asked questions about irbesartan

How long does irbesartan take to work? 
It starts lowering blood pressure within 2-6 hours. The full effect may take up to 4-6 weeks[1]. 

Can I drink alcohol while taking irbesartan? 
Yes, but alcohol can enhance side effects like dizziness. It’s best to limit intake[1]. 

Can I take irbesartan during pregnancy? 
No, it should not be taken during pregnancy, especially after the first trimester, as it can harm the unborn baby[1]. 

Can I take ibuprofen with irbesartan? 
Use with caution, especially if you have kidney problems. Speak to your pharmacist or GP before combining them[1]. 

Can I drive or ride a bike while taking irbesartan? 
Wait and see how you respond before driving or riding a bike. Some people get dizzy when first taking irbesartan[1]. 

Should I avoid any foods while taking irbesartan? 
It’s a good idea to avoid low-sodium salt substitutes such as Lo-Salt, as they’re high in potassium. Combined with irbesartan, this can lead to a spike in your potassium levels[1].  

What should I do if I feel dizzy? 
Sit or lie down until it passes and avoid driving or operating machinery until you feel better[1]. 

Can irbesartan be taken long-term? 
Yes, it’s often used for long-term control of blood pressure and kidney protection[1]. 

For the official NHS guide for irbesartan, visit their website.