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Allopurinol (Allopurinol 100mg tablets)



Information specific to: Allopurinol 100mg tablets when used in Gout.

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

The information in this Medicine Guide for allopurinol varies according to the condition being treated and the particular preparation used.

Your medicine

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.

Whether this medicine is suitable for you

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:

  • are allergic or sensitive to or have had a reaction to any of the ingredients in the medicine
  • have an attack of gout at the moment
  • have heart problems
  • have high blood pressure
  • have kidney problems
  • have liver problems

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

  • to confirm that this is the right dose
  • to determine whether or not the medicine is suitable and whether it must be prescribed with extra care
  • to check that this medicine is not having any undesired effects

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.


Alcohol can interact with certain medicines.

In the case of Allopurinol:

  • there are no known interactions between alcohol and Allopurinol


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:

  • Allopurinol is not known to interact with food. You should continue on the diet advised by your dietician or prescriber

Driving and operating machinery

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:

  • this medicine could affect your ability to drive or operate machinery

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.

Family planning and pregnancy

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 should only take this medicine during pregnancy if your doctor thinks that you need it

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:

  • this medicine passes into breast milk. It is not known if taking Allopurinol and breast-feeding may affect your baby

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.

Taking other medicines

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:

  • 6-mercaptopurine
  • amoxicillin
  • ampicillin
  • azathioprine
  • bleomycin
  • chlorpropamide
  • ciclosporin
  • cyclophosphamide
  • didanosine
  • doxorubicin
  • mechloroethamine
  • phenytoin
  • probenecid
  • procarbazine
  • theophylline
  • vidarabine
  • warfarin

The following types of medicine may interact with Allopurinol:

  • ACE inhibitors
  • coumarin anticoagulants
  • cytotoxics
  • diuretics
  • salicylates
  • uricosuric agents

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

Complementary preparations and vitamins

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.

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