About losartan

Losartan is an angiotensin receptor blocker (also called an angiotensin-II receptor antagonist (AIIRA)). It is used to lower hypertension (high blood pressure). People with high blood pressure often do not feel unwell but, left untreated, high blood pressure can harm the heart and damage blood vessels. Losartan is also used to treat heart failure, which is a condition where your heart is not working as well as it should.

Losartan works by blocking the effect of a chemical called angiotensin II which is made in your bloodstream. Angiotensin II causes your blood vessels to narrow and also leads to the production of another chemical called aldosterone, which increases the amount of fluid in your blood. By preventing the action of angiotensin II, losartan reduces how much work your heart has to do and lowers your blood pressure. It also has a protective effect on your kidneys.

You may be prescribed losartan to take on its own, or alongside other medicines to help your condition. There is a combination tablet available called Cozaar-Comp® which contains losartan and a diuretic called hydrochlorothiazide.

Before taking losartan

Some medicines are not suitable for people with certain conditions, and sometimes a medicine may only be used if extra care is taken. For these reasons, before you start taking losartan it is important that your doctor or pharmacist knows:

• If you are pregnant, trying for a baby or breast-feeding.
• If you know you have a blockage in the artery which supplies blood to your kidneys (this is called renal artery stenosis).
• If you have liver problems.
• If you have been told you have cardiomyopathy (cardiac muscle disease), or aortic stenosis (narrowing of the main blood vessel from your heart), or any other heart problem.
• If you are taking other medicines, including those available to buy without a prescription, herbal and complementary medicines.
• If you have ever had an allergic reaction to a medicine.

How to take losartan

• Before you start this treatment, read the manufacturer's printed information leaflet from inside the pack. The leaflet will give you more information about losartan and a full list of possible side-effects from taking it.
• Take losartan exactly as your doctor has told you to. It is usual to take one tablet daily, although there are several strengths of tablet available. The tablet strength you are prescribed will depend upon the reason why you are taking it. Your dose will be on the label of the pack of tablets to remind you.
• You can take losartan at a time of day you find easy to remember, but try to take your doses at the same time each day. This will help you to avoid missing any doses.
• You can take losartan before or after meals.
• If you forget to take a dose, take it as soon as you remember. If you do not remember until the following day, skip the missed dose. Do not take two doses together to make up for a forgotten dose.

Getting the most from your treatment

• Try to keep your regular appointments with your doctor. This is so your progress can be monitored. Your doctor will want you to have some blood tests from time to time to check on your kidneys and how much potassium is in your blood.
• If you buy any medicines, check with a pharmacist that they are suitable to take with losartan. This is because some anti-inflammatory painkillers (such as aspirin and ibuprofen) may interfere with the way these tablets work, and also increase the risk of side-effects.
• It is very important that you follow any dietary and lifestyle advice that you may have been given by your doctor, such as eating a healthy diet, not smoking, and taking regular exercise.
• If you drink alcohol, ask your doctor for advice about taking losartan and alcohol. Drinking alcohol while you are on losartan may make you feel dizzy and may not be recommended for you.
• Do not use salt substitutes which contain potassium while you are on losartan. This is because they increase the amount of potassium in your blood and this can cause problems.
• If you are having an operation or dental treatment, tell the person carrying out the treatment that you are taking losartan. This is because losartan taken with an anaesthetic may make your blood pressure drop too low.
• Treatment with losartan is usually long-term unless you experience an adverse effect. Continue to take the tablets unless you are advised otherwise.

Can losartan cause problems?

Along with their useful effects, most medicines can cause unwanted side-effects although not everyone experiences them. These usually improve as your body adjusts to the new medicine, but speak with your doctor or pharmacist if any of the following side-effects continue or become troublesome.

Important: if you get any swelling of your mouth or face, speak with your doctor or go to your local accident and emergency department straightaway. These are signs of an allergic reaction.

If you experience any other symptoms which you think may be due to this medicine, speak with your doctor or pharmacist.

How to store losartan

• Keep all medicines out of the reach and sight of children.
• Store the tablets in a cool, dry place, away from direct heat and light.
• Store the liquid medicine in a refrigerator and do not use it after the expiry date on the bottle. The expiry date is four weeks after it has been made up.

Important information about all medicines