An angiotensin receptor blocker (Cozaar)
Can be taken as tablets and oral liquid suspension.
Losartan is an angiotensin receptor blocker. It is also called an angiotensin-II receptor antagonist, or an AIIRA.
- Losartan works by blocking the effect of a substance in your body called Angiotensin II. Angiotensin II causes your blood vessels to narrow, which is a symptom of Raynaud's, and also leads to the production of another substance 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 with a diuretic called hydrochlorothiazide. This combination tablet can be prescribed to people with high blood pressure to help reduce the total number of tablets that need to be taken each day.
Before taking losartan
Some medicines are not suitable for people with certain conditions, and sometimes a medicine can only be used if extra care is taken. For these reasons, before you start taking losartan it is important that your doctor knows:
- If you are pregnant or breast-feeding.
- If you know you have a blockage of the artery which supplies blood to your kidneys, a condition called renal artery stenosis.
- If you have any problems with your heart valves or heart muscle.
- If you have a problem with the way your liver works.
- If you are taking any other medicines. This includes any medicines you are taking which are available to buy without a prescription, such as herbal and complementary medicines.
- If you have ever had an allergic reaction to a medicine, or if you have had any other type of allergic reaction.
How to take Losartan
- Before you start the treatment, read the manufacturer's printed information leaflet from inside the pack. It will give you more information about losartan and will provide you with a full list of the side-effects which you could experience from taking it.
- Take losartan once each day, exactly as your doctor tells you to. There are several different strengths of tablet available. When you first start treatment your doctor may gradually increase the strength of the tablets to suit your condition. Each time you collect a fresh supply, it's a good idea to check the strength on the packet to make sure they are what you are expecting.
- Try to take losartan at the same time of day each day. For most people this will be in the morning. Taking your doses at the same time each day will help you to remember to take losartan regularly.
- Swallow the tablet with a drink of water. You can take losartan either before or after a meal.
- If you forget to take a dose, take it as soon as you remember. If you do not remember until the following day, miss out the forgotten dose. Do not take two doses at the same time 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 may want you to have some blood tests from time to time to check on your kidneys, and also 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) can interfere with the way it works, and also may increase the risk of side-effects.
- It is very important that you follow any dietary and lifestyle advice that you 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. Your doctor may recommend that you do not drink alcohol while you are on losartan because it will increase the risk of side-effects, such as feeling dizzy or faint.
- Try to avoid salt substitutes which contain potassium. This is because the substitutes will 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 your blood pressure may drop too low if you are given some anaesthetics.
- Treatment with losartan is usually long-term unless you experience an adverse effect. Continue to take the tablets regularly, unless you are advised otherwise by your doctor.
Can losartan cause problems?
Along with their useful effects, most medicines can cause unwanted side-effects although not everyone experiences them. The list below contains some of the most common ones associated with losartan. You will find a full list in the manufacturer's information leaflet supplied with your medicine. The unwanted effects often improve as your body adjusts to the new medicine, but speak with your doctor or pharmacist if any of the following continue or become troublesome.
If you experience any symptoms which you think may be due to the medicine, speak with your doctor or pharmacist for further advice.
It is very important that your doctor check your progress at regular visits to make sure that this medicine is working properly. Blood and urine tests may be needed to check for unwanted effects.
Using this medicine while you are pregnant can harm your unborn baby. Use an effective form of birth control to keep from getting pregnant. If you think you have become pregnant while using this medicine, tell your doctor right away.
Dizziness or lightheadedness may occur after the first dose of this medicine, especially if you have been taking a diuretic (water pill). Make sure you know how you react to this medicine before you drive, use machines, or do anything else that could be dangerous if you are dizzy or not alert.
Check with your doctor right away if you become sick while taking this medicine, especially if you have severe or continuing nausea, vomiting, or diarrhea that does not stop. These conditions may cause you to lose too much water and may lead to low blood pressure. You can also lose water by sweating, so drink plenty of water during exercise or in hot weather.
Ask your doctor before you use medicines, supplements, or salt substitutes that contain potassium.
Avoid alcoholic beverages until you have discussed their use with your doctor. Alcohol may make the low blood pressure effect worse or increase the possibility of dizziness or fainting.
Do not take other medicines unless they have been discussed with your doctor. This especially includes prescription or nonprescription (over-the-counter [OTC]) medicines for appetite control, asthma, colds, cough, hay fever, or sinus problems, and herbal or vitamin supplements. Most common side effects:
- Abdominal or stomach pain
- bladder pain
- bloody or cloudy urine
- blurred vision
- cold sweats
- cool, pale skin
- difficult breathing
- difficult, burning, or painful urination
- fast heartbeat
- frequent urge to urinate
- increased hunger
- irregular heartbeat
- lower back or side pain
- nausea or vomiting
- numbness or tingling in the hands, feet, or lips
- pale skin
- shortness of breath
- slurred speech
- troubled breathing with exertion
- unusual bleeding or bruising
- unusual tiredness or weakness
- weakness or heaviness of the legs
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 by the pharmacy.