Irbesartan

What is Irbesartan?

Irbesartan is a type of medicine known as an angiotensin receptor blocker (ARB) which is used to treat high blood pressure. It also helps to prevent strokes, heart attacks and kidney problems by lowering blood pressure.

How does Irbesartan work?

Irbesartan works by blocking the actions of a hormone called angiotensin II. Angiotensin II normally acts to constrict the blood vessels, causing the blood pressure to increase. By blocking the action of this hormone, the blood vessels are wider and more relaxed, making it easier to pump blood around the body and reducing the blood pressure. Angiotensin II also promotes salt and water retention, which can increase blood pressure. Blocking the action of angiotensin II, therefore, reduces salt and water retention and reduces blood pressure.

How long does Irbesartan take to work?

Irbesartan will start to work after 3–6 hours. However, it can take 4-6 weeks for the medication to take full effect. High blood pressure often produces no symptoms so you may not feel any different after taking Irbesartan. This does not mean that the medication isn't working.

How do I know if I have high blood pressure?

High blood pressure is diagnosed following a blood pressure test. This can be done at your GP surgery by a doctor, nurse or healthcare assistant. It can also be done at certain pharmacies or at home with a self-testing blood pressure monitor. If you are at risk of high blood pressure then it's recommended that you get checked up regularly. Risk factors include:

• Age  – if you are over 40 then you should have your blood pressure checked every 5 years 
• Family history 
• African or Caribbean ethnicity 
• A diet that is high in salt 
• Not getting exercise 
• Being overweight 
• Drinking lots of alcohol 
• Smoking 
• Long-term poor sleeping habits

What causes high blood pressure?

There are several possible causes of high blood pressure which may include underlying health conditions, particular medications and lifestyle risk factors. Health conditions that may predispose you to blood pressure include: 

• Kidney disease 
• Diabetes 
• Persistent kidney infections 
• Obstructive sleep apnoea 
• Glomerulonephritis 
• Narrowed arteries around the kidneys 
• Underactive thyroid 
• Overactive thyroid 
• Cushing's syndrome 
• Acromegaly 
• Hyperaldosteronism
• Phaeochromocytoma 
• Lupus 
• Scleroderma 

 Medicines that may cause high blood pressure include: 

• The combined oral contraceptive pill 
• Steroids 
• Non-steroidal anti-inflammatories 
• Some types of cough and cold remedies 
• Liquorice based herbal remedies 
• Recreational drugs, mainly cocaine and amphetamines 
• SSRI antidepressants

What are the risks of high blood pressure?

On average, high blood pressure affects 1 in 4 adults within the UK. If it is left unnoticed or untreated then it leaves you at risk of experiencing serious conditions or health problems. These include: 

• Heart attacks
• Heart disease 
• Heart failure 
• Aortic aneurysm
• Stroke
• Kidney disease 
• Vascular dementia 
• Peripheral arterial disease 

 Managing your blood pressure by using medication and adjusting your lifestyle habits reduces your risk of experiencing these circumstances.

Active ingredients

The active ingredient in the medicine is Irbesartan. 

Each tablet contains either a 75mg, 150mg or 300mg dose. 

Inactive ingredients

The inactive ingredients contained in Irbesartan are lactose monohydrate, croscarmellose sodium (E468), cellulose microcrystalline (E460), hypromellose E5 (E464), silica (E551), magnesium stearate (E572), macrogol 400 and titanium dioxide (E171).

Please note that different generic manufacturers may contain different inactive ingredients. 

Which ingredients can cause an allergic reaction?

A severe allergic reaction to Irbesartan is a rare occurrence. However, if you are using the medication for the first time, you should look out for the signs of a severe allergic reaction which include difficulty breathing, hives, swelling of your eyes/lips/face and severe dizziness. If you develop any of these symptoms after taking the medication, please visit your local emergency department right away for medical attention.

How to take Irbesartan

Irbesartan should be taken once a day. Swallow the tablet whole with a full glass of water at around the same time each day. The medicine can be taken with or without food. Always take Irbesartan as your doctor has prescribed and continue to take it unless your doctor tells you to stop. 

How to take Irbesartan?

Irbesartan should be taken once a day. Swallow the tablet whole with a glass of water at around the same time each day. You may be advised to take the tablet at night before bedtime. The medicine can be taken with or without food. Always take Irbesartan as your doctor has prescribed and continue to take it unless your doctor tells you to stop.

How long should I take Irbesartan for?

Irbesartan is taken long term. It may be the case that you will need to take the medication for the rest of your life to keep your blood pressure under control. 

What should I do if I forget to take Irbesartan?

If you forget to take Irbesartan, leave the missed dose and take the next one at your usual time. Do not take double the dose to make up for a missed one. 

What should I do if I take too much Irbesartan?

If you take too much Irbesartan by mistake, tell your doctor right away. 

What should I do if Irbesartan makes me vomit?

You may experience side effects when you first start taking Irbesartan. This may include nausea and vomiting. If this happens consistently, see your doctor for advice. They may advise you to stop taking the medicine until you feel better.

Common side effects include: 

• Abdominal pain
• Physical weakness or lack of energy
• Back pain
• Cough
• Diarrhoea
• Dizziness, particularly after standing up
• Headache
• An increased level of potassium recorded in blood tests 
• Low blood pressure 
• Nausea or vomiting
• Changes to kidney function
• Muscle or joint pain

 Uncommon side effects may include: 

• Skin swelling or rash
• Other skin reactions
• Reduced platelet count
• Chest pain
• Indigestion
• Liver disorders
• Sexual dysfunction
• Tachycardia (fast heartbeat)

Other side effects (frequency not known) may include: 

• Hypersensitivity vasculitis (inflammation of the small blood vessels causing a blotchy rash)
• Muscle cramps
• Altered taste
• Tinnitus (ringing in the ears)

Serious side effects are rare, however, if you experience any of the following then seek medical attention: 

• Rash, swelling of the face, lips or tongue, wheezing or difficulty breathing – this may indicate an allergic reaction
• Yellowing of the skin or whites of the eyes – this can indicate a liver problem
• Purple spots on the skin or unexpected bruising or bleeding – this may indicate a blood disorder
• Weakness, an irregular heartbeat or palpitations, pins and needles or muscle cramps – these can be signs of changes in the salt levels in your blood

Contraindications

Do not take Irbesartan if: 

• You are allergic to any of the ingredients contained in the medicine 
• You are more than 3 months pregnant 

 Tell your doctor if any of the following apply to you before taking Irbesartan: 

• You have diabetes 
• You are under 18 or over 65
• You experience excessive vomiting or diarrhoea 
• You have kidney problems including renal artery stenosis or a kidney transplant
• You have heart problems, including heart failure or problems with the heart valves
• You have liver problems
• You are scheduled to have an operation 
• You are pregnant or trying to get pregnant 
• You are breastfeeding
• You are of black African or African-Caribbean origin
• You have a history of angioedema (rapid swelling of the skin)
• You have primary aldosteronism
• You have been on a low-salt diet
• You have low blood pressure

Drug Interactions

Let your doctor know if you are taking any other types of medication. In particular, the following medications may require additional care: 

• Other medications to lower your blood pressure e.g. Ramipril, Enalapril, Aliskiren 
• Potassium supplements 
• Salt substitutes containing potassium 
• Diuretics e.g. Bendroflumethiazide, Indapamide
• Lithium 
• Non-steroidal anti-inflammatories such as ibuprofen, naproxen
• Aspirin
• Heparin
• Spironolactone

Irbesartan and alcohol

It's best to avoid drinking alcohol for the first few days of taking Irbesartan as alcohol can enhance the blood pressure lowering action of the medication, resulting in dizziness or feeling light-headed. If you experience dizziness while taking Irbesartan then avoid drinking alcohol.

Irbesartan and pregnancy

Irbesartan is not usually recommended during early pregnancy and it can cause harm to an unborn baby if it is taken after the third month of pregnancy. Tell your doctor if you are, or could be, pregnant so that they can prescribe you a medication that is suitable.

Irbesartan and breastfeeding

Irbesartan is not recommended for breastfeeding mothers as a small amount of the medicine may pass through the breast milk. Your doctor will be able to recommend a suitable alternative to Irbesartan. 

Will Irbesartan affect my fertility?

Irbesartan will not have an effect on your fertility but it should not be taken if you are trying to get pregnant. 

Will Irbesartan affect my contraception?

Irbesartan will not affect any type of contraception. Certain types of hormonal contraceptives are not suitable for women with high blood pressure, such as the combined pill. 

Can I drive while taking Irbesartan?

It's recommended not to drive until you know how Irbesartan affects you. It can cause dizziness or fatigue in some people. If this happens, avoid driving or operating machinery until you feel better. 

Is Irbesartan addictive?

Irbesartan has not been known to be addictive. 

Alternatives to Irbesartan

Candesartan, Losartan and Valsartan are alternative ARBs (angiotensin receptor blockers) which work in the same way as Irbesartan. Other types of high blood pressure medications include: 

• ACE inhibitors (angiotensin-converting enzyme inhibitors) – these are usually offered in the first instance for patients under the age of 55. These include Benazepril, Perindopril and Ramipril 
• Calcium-channel blockers such as Amlodipine, Felodipine or Verapamil 
• Beta-blockers such as Bisoprolol and Propranolol 
• Diuretics such as Indapamide and Hydrochlorothiazide

Can lifestyle changes help?

Everyone with high blood pressure is advised to make the following lifestyle changes to help lower and maintain your blood pressure: 

• Reduce your salt intake to a maximum of 6g a day
• Eat a low fat, healthy diet that includes 5 portions of fruit and vegetables a day 
• Get at least 30 minutes of exercise per day
• Reduce your consumption of alcohol 
• Maintain a healthy weight 
• Cut down on caffeine
• Quit smoking 

 These steps can be implemented to help prevent high blood pressure from occurring or getting to the point of needing medication.

Is Irbesartan safe to take for a long time?

Irbesartan is designed for long term use so it is safe to take in this way. 

Can I stop taking Irbesartan now that my blood pressure is lower?

You should keep taking Irbesartan even if your blood pressure has lowered. If you stop taking it this could cause your blood pressure to rise again. You will need to keep taking the medication to maintain a healthy blood pressure level. 

Is there any food or drink I should avoid?

You should avoid using salt substitutes, for example, Lo-Salt, while you are taking Irbesartan. This is because it can cause the level of potassium in your blood to become too high.

Can I take Irbesartan for migraines?

Irbesartan is not designed to treat migraines.

Can I take Irbesartan to prevent Alzheimer's disease?

While studies have taken place to find out whether or not blood pressure medications can help to prevent the onset of Alzheimer's, there is not enough evidence to suggest that the medication can work in this manner. 

How to prevent high blood pressure

High blood pressure can be prevented by: 

• Eating a healthy diet

• Cutting down on fats 

• Reducing your alcohol consumption 

• Losing weight if you are overweight 

• Staying active 

• Cutting down on caffeine 

• Quitting smoking 

• Getting enough sleep