Allopurinol (Al-loh-pew-rin-oll) is a medicine which is used in prevention of calcium oxalate renal stones, prevention of gout and prevention of hyperuricaemia.

To get the most benefit from your medicine, take it exactly as prescribed. You should also take care to look after your medicine.

This medicine may be available from different manufacturers and in several different forms and so you should check the Patient Information Leaflet or the medicine label for exact details on when and how to take it and how to look after it.

Allopurinol belongs to a class of medicines called anti-gout medicines. It is used to prevent gout, kidney stones, or hyperuricaemia during cancer treatment. Allopurinol works by slowing down the production of a chemical in the body called uric acid.

Uric acid is a chemical that is made naturally in the body. Sometimes, the uric acid level in the body can sometimes become too high and cause gout, kidney stones, or other problems. Over-eating certain types of foods, using certain types of medicines, and having treatment for cancer, can all make the uric acid level higher.

Allopurinol reduces the amount of uric acid in the body by blocking one of the processes that makes it. This helps to stop the level of uric acid in the blood from becoming too high and causing problems like gout or kidney stones.

Do not share your medicine with other people. It may not be suitable for them and may harm them.

The pharmacy label on your medicine tells you how much medicine you should take. It also tells you how often you should take your medicine. This is the dose that you and your prescriber have agreed you should take. You should not change the dose of your medicine unless you are told to do so by your prescriber.

If you feel that the medicine is making you unwell or you do not think it is working, then talk to your prescriber.

Some medicines work best if they are taken at a specific time of day. Getting the most benefit from your medicine can also be affected by what you eat, when you eat and the times at which you take other medicines.

Specific information on when to take Allopurinol can be found in the Patient Information Leaflet that comes with this medicine or on the medicine label. You can also ask your doctor or pharmacist for information about when to take your medicine.

Some medicines have specific instructions about how to take them. This is because they work better when taken correctly. These instructions can include getting the right dose and special instructions for preparing the medicine.

Specific information on how to take Allopurinol can be found in the Patient Information Leaflet that comes with this medicine or on the medicine label. Alternatively, you can request information about how to take your medicine from your doctor or pharmacist.

If you are having problems taking this form of Allopurinol, you should talk to your prescriber or pharmacist. They may be able to give you advice on other ways to take your medicine or other preparations that are easier for you to take.

Taking extra doses of some medicines can be harmful. In some cases even one extra dose can cause you problems. If you take extra doses of your medicine, you must get medical advice immediately. You may need a test to assess the effect of taking extra doses. This is because the effects of taking too much medicine are very complex so it is very important that you seek medical advice.

Contact your prescriber, pharmacist, specialist clinic or NHS Direct on 0845 46 47 for advice.

Make sure you take all of your medicine containers with you if you are advised to go to hospital.

Suddenly stopping your medicine may cause your original condition to return. This is why you must speak to your prescriber if you are having any problems taking your medicine.

If you are not having any problems taking this medicine then do not stop taking it, even if you feel better, unless advised to do so by your prescriber.

If you are in any doubt, contact your prescriber, pharmacist, specialist clinic or NHS Direct on 0845 46 47.

The instructions on how you should keep your medicine are on the pharmacy label. It is a good idea to keep your medicine in the original container. This will help to keep your medicine in the best condition and also allow you to check the instructions. Do not take the medicine if the packaging appears to have been tampered with or if the medicine shows any signs of damage. Make sure that the medicine is out of the sight and reach of children.

Specific information on how to look after Allopurinol can be found in the Patient Information Leaflet that comes with this medicine or on the medicine label. Alternatively, you can request information about how to look after your medicine from your doctor or pharmacist.

You must not take the medicine after the expiry date shown on the packaging. If you have any unused medicine, return it to your pharmacist who will dispose of it safely.

Your prescriber will not give you this medicine if they know of any reasons why you must not take it. Sometimes it is necessary to prescribe this medicine with extra caution. For more information see the ‘Whether this medicine is suitable for you’ section.

If you have been prescribed this medicine you need to be aware of the side-effects that you could develop while taking this medicine. For more information see the 'Side-effects' section.

Allopurinol is not suitable for everyone and some people should never use it. Other people should only use it with special care. It is important that the person prescribing this medicine knows your full medical history.

Your prescriber may only prescribe this medicine with special care or may not prescribe it at all if you:

As part of the process of assessing suitability to take this medicine a prescriber may also arrange tests:

Over time it is possible that Allopurinol can become unsuitable for some people, or they may become unsuitable for it. If at any time it appears that Allopurinol has become unsuitable, it is important that the prescriber is contacted immediately.

A medicine is only made available to the public if the clinical trials have shown that the benefits of taking the medicine outweigh the risks.

Once a medicine has been licensed, information on the medicine's effects, both intended and unintended, is continuously recorded and updated.

Some side-effects may be serious while others may only be a mild inconvenience.

Everyone's reaction to a medicine is different. It is difficult to predict which side-effects you will have from taking a particular medicine, or whether you will have any side-effects at all. The important thing is to tell your prescriber or pharmacist if you are having problems with your medicine.

Common: More than 1 in 100 people who take Allopurinol

• hypersensitivity reactions including skin reactions, Stevens-Johnson syndrome or toxic epidermal necrolysis, which can be fatal. You should seek immediate medical advice if you develop a rash, fever, itching, scaly or flaking skin, unexplained or easy bruising of the skin or mucous membranes, angioedema or anaphylactic shock. Some types of skin reactions may occur with joint pains, lymphadenopathy, liver problems, kidney problems or seizures

Uncommon: More than 1 in 1000 people who take Allopurinol

• vomiting
• nausea
• abnormal laboratory test results

Very rare: Fewer than 1 in 10,000 people who take Allopurinol

• blood and bone marrow problems
• diabetes
• high levels of lipids in the blood
• depression
• coma
• paralysis
• coordination problems
• neuropathies
• paraesthesiae
• sleepiness
• headaches
• taste changes
• eye or eyesight problems
• vertigo
• angina
• slower heart rate
• raised blood pressure
• vomiting blood
• steatorrhoea
• mouth problems
• bowel routine changes
• hair loss
• hair colour changes
• blood in the urine
• infertility
• erectile dysfunction
• breast enlargement in men
• oedema
• general feeling of being unwell
• weakness

The frequency of these side-effects is unknown

• attacks of gout or worsening of gout

If you feel unwell or if you have concerns about a side-effect, you will need to seek advice. If you feel very ill, get medical help straight away. Contact your prescriber, pharmacist, nurse or call NHS Direct on 0845 46 47.

If you have been prescribed this medicine you and your prescriber may need to think about whether you need to change any of your everyday activities. You must also discuss with your prescriber any other medicines and any complementary preparations you are taking.

If you are taking more than one medicine they may interact with each other. At times your prescriber may decide to use medicines that interact, in other cases this may not be appropriate.

The decision to use medicines that interact depends on your specific circumstances. Your prescriber may decide to use medicines that interact, if it is believed that the benefits of taking the medicines together outweigh the risks. In such cases, it may be necessary to alter your dose or monitor you more closely.

Tell your prescriber the names of all the medicines that you are taking so that they can consider all possible interactions. This includes all the medicines which have been prescribed by your GP, hospital doctor, dentist, nurse, health visitor, midwife or pharmacist. You must also tell your prescriber about medicines which you have bought over the counter without prescriptions.

The following medicines may interact with Allopurinol:

The following types of medicine may interact with Allopurinol:

If you are taking Allopurinol and one of the above medicines or types of medicines, make sure your prescriber knows about it.

Medicines can interact with complementary preparations and vitamins. In general, there is not much information available about interactions between medicines and complementary preparations or vitamins.

If you are planning to take or are already taking any complementary preparations and vitamins you should ask your prescriber whether there are any known interactions with Allopurinol.

Your prescriber can advise whether it is appropriate for you to take combinations that are known to interact. They can also discuss with you the possible effect that the complementary preparations and vitamins may have on your condition.

If you experience any unusual effects while taking this medicine in combination with complementary preparations and vitamins, you should tell your prescriber.

When taking any medicine you should be aware that it might interfere with your ability to drive or operate machinery safely.

In the case of Allopurinol:

You should see how this medicine affects you before you judge whether you are safe to drive or operate machinery. If you are in any doubt about whether you should drive or operate machinery, talk to your prescriber.

Medicines can interact with certain foods. In some cases, this may be harmful and your prescriber may advise you to avoid certain foods.

In the case of Allopurinol:

Alcohol can interact with certain medicines.

In the case of Allopurinol:

Taking this medicine could have an impact on your decisions relating to family planning, pregnancy and breast-feeding.

Most medicines, in some way, can affect the development of a baby in the womb. The effect on the baby differs between medicines and also depends on the stage of pregnancy that you have reached when you take the medicine.

In the case of Allopurinol:

You need to discuss your specific circumstances with your doctor to weigh up the overall risks and benefits of taking this medicine. You and your doctor can make a decision about whether you are going to take this medicine during pregnancy.

If the decision is that you should not have Allopurinol, then you should discuss whether there is an alternative medicine that you could take during pregnancy.

Certain medicines can pass into breast milk and may reach your baby through breast-feeding.

In the case of Allopurinol:

Before you have your baby you should discuss breast-feeding with your doctor or midwife. They will help you decide what is best for you and your baby based on the benefits and risks associated with this medicine. You should only breast-feed your baby while taking this medicine on the advice of your doctor or midwife.

Medicines contain active ingredients. They may also contain other, additional ingredients that help ensure the stability, safety and effectiveness of the medicine. They are also added to improve the medicine's taste and appearance and to make it easier to take. Some may be used to prolong the life of the medicine.

This medicine contains allopurinol.

We are unable to list all of the ingredients for your medicine here. For a full list, you should refer to the patient information leaflet that comes with this medicine. You should check that you are able to take the ingredients of your medicine, especially if you have any allergies. You should also check whether any of these ingredients are known to have side-effects.

If you are not able to take any of the ingredients in your medicine, talk to your prescriber or pharmacist to see if they can suggest an alternative medicine. If you have reacted badly to Allopurinol before, do not take Allopurinol. Talk to your prescriber, pharmacist or nurse as soon as possible.