Irbesartan Tablets

High blood pressure is a long-term condition that often requires ongoing treatment to protect your heart, blood vessels, and kidneys from the damage that sustained raised pressure can cause. Irbesartan tablets are a prescription-only angiotensin receptor blocker (ARB) used in adults to treat hypertension and to protect the kidneys in adults with type 2 diabetes who also have high blood pressure and kidney disease. A prescription can only be issued following a clinical consultation.

Irbesartan tablets are an oral prescription medicine containing irbesartan as the active ingredient. Irbesartan belongs to the angiotensin receptor blocker (ARB) class of medicines, also known as angiotensin II receptor antagonists. The ARB class works on the renin angiotensin system and is widely used in cardiovascular therapy for blood pressure control.

Irbesartan is licensed in the UK for two indications. The first is the treatment of hypertension (high blood pressure) in adults. The second is the treatment of kidney disease (nephropathy) in adult patients with type 2 diabetes and high blood pressure. In this second indication, irbesartan helps to slow the progression of kidney disease by reducing the pressure inside the kidney's filtering units.

Irbesartan is available as a generic medicine from multiple manufacturers. Three strengths are available through this service: 75 mg, 150 mg, and 300 mg. The appropriate strength for you will be determined by your prescriber based on your blood pressure, response to treatment, and any existing kidney conditions.

Irbesartan works by acting on the renin angiotensin system, a key hormonal pathway involved in blood pressure regulation and kidney function.

The Renin Angiotensin System and Angiotensin II

The renin angiotensin system regulates blood pressure partly through a hormone called angiotensin II. Angiotensin II causes blood vessels to narrow and signals the body to retain sodium and water, both of which raise blood pressure. It also increases the pressure within the small blood vessels of the kidneys, which over time can damage the filtering units and contribute to the progression of diabetic kidney disease.

Blocking the Angiotensin II Receptor

Irbesartan works by blocking the receptor that angiotensin II binds to (the AT1 receptor). By occupying this receptor without activating it, irbesartan prevents angiotensin II from exerting its effects. Blood vessels relax and widen, sodium and water retention is reduced, and blood pressure falls. In the kidneys, blocking the AT1 receptor also reduces pressure within the glomeruli, which helps to protect kidney function in patients with diabetic nephropathy.

Unlike ACE inhibitors, ARBs such as irbesartan do not inhibit the breakdown of bradykinin. This means irbesartan does not typically cause the dry cough that is a common reason patients switch away from ACE inhibitors. This makes irbesartan a suitable alternative antihypertensive medication for patients who cannot tolerate ACE inhibitors due to cough.

Always take irbesartan exactly as your prescriber instructs. The information below summarises key points from the current UK SmPC. Read the Patient Information Leaflet supplied with your medicine before starting treatment.

• Take one tablet once daily, at approximately the same time each day.
• Irbesartan can be taken with or without food.
• Swallow the tablet whole with a glass of water.
• If you miss a dose, take it as soon as you remember on the same day. If you only remember the following day, skip the missed dose and continue with your normal schedule. Do not take two doses on the same day.
• Do not stop taking irbesartan without speaking to your prescriber first, even if you feel well. Blood pressure often causes no symptoms, and stopping treatment can allow it to rise again.
• Your prescriber may start you on a lower dose of irbesartan and increase it gradually based on your blood pressure response. Regular blood pressure checks and, where relevant, kidney function and potassium monitoring will help your prescriber assess how well treatment is working. Attend any follow up appointments your prescriber recommends.

Irbesartan tablets are available in three strengths. The appropriate dose will be determined by your prescriber based on your blood pressure, the indication being treated, and your individual clinical response.

Irbesartan 75 mg Tablets

The 75 mg tablet is the lowest available strength. It is typically used as the starting dose for patients who may be more sensitive to blood pressure lowering medicines, including older patients, those with mild to moderate kidney impairment, or those initiating antihypertensive medication for the first time. It allows the prescriber to assess tolerability before any dose increase.

Irbesartan 150 mg Tablets

The 150 mg tablet is the standard starting dose for most adults with hypertension. After four weeks of treatment, if blood pressure is not adequately controlled at 150 mg once daily, the prescriber may consider increasing the dose to 300 mg. For patients with type 2 diabetes and kidney disease, the 150 mg dose is also used as the starting dose, with subsequent titration based on tolerability and kidney function.

Irbesartan 300 mg Tablets

The 300 mg tablet is the maximum recommended daily dose. It is used when blood pressure has not been adequately controlled on the 150 mg dose. In patients with type 2 diabetes and nephropathy, the target maintenance dose is 300 mg once daily, as this is the dose that has been studied in clinical trials for this indication and is referenced in the UK SmPC. All dose adjustments are clinical decisions made by your prescriber.

Do not take more than 300 mg of irbesartan per day. If irbesartan alone does not achieve adequate blood pressure control, your prescriber may add a second antihypertensive medicine rather than exceeding the maximum dose.

Like all medicines, irbesartan can cause side effects, although not everyone experiences them. The information below is based on the current UK SmPC. Refer to the Patient Information Leaflet for the full list of side effects.

Common Side Effects (may affect up to 1 in 10 people)

• Dizziness, particularly on standing up quickly
• Nausea or vomiting
• Fatigue
• Raised potassium levels (hyperkalaemia), particularly in patients with kidney disease or diabetes. Regular blood tests help to detect and manage this.

Uncommon Side Effects (may affect up to 1 in 100 people)

• Low blood pressure, especially with the first dose or in patients who are dehydrated
• Headache
• Skin rash or itching
• Changes in kidney function, particularly in patients with pre existing kidney disease or narrowing of the arteries supplying the kidneys

Rare Side Effects (may affect up to 1 in 1,000 people)

• Raised liver enzymes or jaundice. Report any yellowing of the skin or whites of the eyes to your doctor promptly.
• Muscle pain (myalgia) or joint pain (arthralgia)

Serious Side Effects: Seek Urgent Medical Attention

Contact your doctor or go to your nearest accident and emergency department promptly if you experience:

• Angioedema: sudden swelling of the face, lips, tongue, or throat. This is a rare but potentially serious reaction. Although angioedema occurs less commonly with ARBs than with ACE inhibitors, it has been reported and requires immediate emergency assessment.
• Signs of severely raised potassium such as muscle weakness, an irregular heartbeat, or confusion
• Significant worsening of kidney function such as a marked reduction in urine output

Report any suspected side effect to your prescriber, pharmacist, or via the MHRA Yellow Card scheme at yellowcard.mhra.gov.uk.

Irbesartan Tablets May Be Suitable If You:

• Are an adult aged 18 or over with a confirmed diagnosis of hypertension
• Have type 2 diabetes with high blood pressure and established kidney disease
• Cannot tolerate ACE inhibitors due to a persistent dry cough and require an alternative antihypertensive medication in the ARB class
• Are already prescribed irbesartan and require a repeat prescription through an online prescribing service

Irbesartan Tablets Are Not Suitable If You:

• Are pregnant or planning to become pregnant. Irbesartan is contraindicated in pregnancy. ARBs can cause serious harm to the developing baby, including kidney damage and foetal death, particularly in the second and third trimesters. Contact your prescriber immediately if you become pregnant while taking irbesartan.
• Are breastfeeding
• Have diabetes or moderate to severe kidney impairment and are also taking aliskiren. The combination of an ARB and aliskiren is contraindicated in these patients.
• Have a known allergy or hypersensitivity to irbesartan or any excipient listed in the SmPC
• Are under 18 years of age

Tell your prescriber about all medicines you take, including over the counter products and herbal supplements. The following interactions are of particular clinical importance:

• Potassium supplements, potassium-sparing diuretics (such as spironolactone or amiloride), and potassium-containing salt substitutes: these can raise blood potassium to dangerous levels when combined with irbesartan.
• NSAIDs such as ibuprofen: regular use can reduce the blood pressure lowering effect of irbesartan and may increase the risk of kidney problems.
• Lithium: ARBs can increase lithium blood levels, raising the risk of lithium toxicity. Close monitoring is required if this combination is used.
• Aliskiren: contraindicated in combination with irbesartan in patients with diabetes or significant kidney impairment.
• Other antihypertensive medicines and diuretics: combining irbesartan with these medicines can enhance the blood pressure lowering effect and may increase the risk of low blood pressure.

Your prescriber will carry out a full clinical assessment, including a review of your current medicines, before any prescription is considered.

Irbesartan is a Prescription Only Medicine. The clinical consultation is the essential first step. A prescription will only be issued if a registered prescriber concludes, based on their individual assessment of your circumstances, that irbesartan is clinically appropriate for you.

During your online consultation with Pharmacy Planet, a registered prescriber will review the clinical information you provide. This includes your blood pressure history, whether you have type 2 diabetes with kidney disease, your current medicines, your kidney function results where available, and any other relevant medical history. Based on this assessment, the prescriber will decide whether irbesartan is appropriate, which strength is suitable, or whether an alternative approach is more appropriate.

If you are being managed for hypertension, diabetes, or kidney disease by your GP, diabetologist, or nephrologist, please keep them informed of all medicines prescribed through online services. Consistent communication between all your healthcare providers supports safe and effective BP regulation and cardiovascular therapy.

• Store below 30°C.
• Store in the original packaging to protect from moisture and light.
• Keep out of the sight and reach of children.
• Do not use after the expiry date printed on the packaging.
• Do not dispose of medicines via household waste or wastewater. Return unused or out of date tablets to your pharmacist for safe disposal.
• Full storage instructions are provided in the Patient Information Leaflet supplied with your medicine.

The table below compares ARB tablets and Rasilez (aliskiren), the only direct renin inhibitor licensed for hypertension in the UK. All act on the renin-angiotensin-aldosterone system (RAAS) and are taken once daily as tablets.

Important: This comparison is for general information only and does not replace medical advice. A prescriber will decide which treatment is suitable for you following an online consultation.

Pharmacy Planet is a GPhC-registered online pharmacy providing access to prescription medicines through a clinically led consultation process. Our registered prescribers and pharmacists are committed to patient safety, accurate clinical information, and responsible prescribing.

We follow GPhC standards, MHRA guidance, and ASA advertising regulations in all aspects of our service. Every prescription is reviewed and dispensed by qualified healthcare professionals. Our aim is to support you with the accurate, balanced information you need to understand your antihypertensive medication and make informed decisions about your health.

If you have questions about irbesartan, blood pressure control, cardiovascular therapy, or any other medicine, our pharmacy team is available to help. We are committed to transparent, patient centred care.

References

1. Electronic Medicines Compendium (eMC). Irbesartan 75 mg, 150 mg and 300 mg tablets — Summary of Product Characteristics. https://www.medicines.org.uk/emc. Accessed May 2026.
2. National Institute for Health and Care Excellence (NICE). Hypertension in adults: diagnosis and management. NICE guideline NG136. https://www.nice.org.uk/guidance/ng136. Accessed May 2026.
3. NHS. High blood pressure (hypertension). https://www.nhs.uk/conditions/high-blood-pressure-hypertension. Accessed May 2026.
4. Joint Formulary Committee. British National Formulary (BNF). Irbesartan. BMJ Group and Pharmaceutical Press. https://bnf.nice.org.uk. Accessed May 2026.
5. Medicines and Healthcare products Regulatory Agency (MHRA). Yellow Card — report a side effect. https://yellowcard.mhra.gov.uk. Accessed May 2026.