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Updated April 2022
Allopurinol (brand names Allohexal, Allosig, Progout, Zyloprim) is a medicine used to treat gout, which is a type of arthritis caused by a build up of uric acid crystals in the joints. Cells produce uric acid normally. In gout the body does not flush it out fast enough.
Allopurinol works by reducing the amount of uric acid made by cells. This helps prevent uric acid crystals building up in the joints and therefore helps prevent joints becoming swollen and painful.
Allopurinol is taken on a long-term basis to prevent attacks of gout. The treatment also helps to prevent permanent damage to the joints. It does not treat the pain or inflammation of an ‘attack’ of gout.
Allopurinol does not work straight away. It may take several weeks to reduce the level of uric acid so you may continue to have gout attacks for some time.
Sometimes starting allopurinol or increasing the dose can actually cause an attack of gout. This does not mean the medicine is not working, so keep taking it during such attacks together with any other medicine your doctor may recommend to manage pain.
To reduce the risk of a gout attack, medicines such as colchicine or anti-inflammatory drugs may be recommended before or at the same time allopurinol is started. Your doctor will advise you about how these medicines should be taken.
Allopurinol is not a pain reliever. You should continue to take allopurinol during an attack, but your doctor will also recommend medicines to treat pain and inflammation. These may include paracetamol, colchicine, anti-inflammatory drugs such as naproxen (Naprosyn), ibuprofen (Brufen/Nurofen), indomethacin (Indocid) or steroids such as prednisolone.
It is a good idea to plan with your doctor what to do if a gout attack occurs and to have symptom controlling medicine ready to use if needed. It is also important that you tell your doctor if your condition persists or worsens.
Allopurinol is taken by mouth as a tablet. It is usually taken once a day.
It should be taken after food to reduce stomach upset. It should also be taken with plenty of water.
For greatest benefit, allopurinol should be taken regularly. To help you remember, take it at the same time(s) each day.
If you forget to take a dose, there is no need to double the dose at the next scheduled dose time.
Tablets come in 100mg or 300mg strengths. Treatment should start with a small dose, increasing over time to between 100mg and 300mg per day. Higher doses (up to 900mg per day) are needed in some cases. If you have kidney problems the dose may need to be lower. The dose is modified according to the level of uric acid in the blood.
Allopurinol may be taken in combination with other arthritis medicines, including:
Treatment with allopurinol may be continued indefinitely as long as it is effective and as long as no serious side effects occur.
If you stop allopurinol treatment there is a high risk that your gout may recur. It is very important not to stop your treatment unless advised by your doctor or unless side effects develop.
Most people do not experience side effects from allopurinol. Tell your doctor if you are concerned about any possible side effects.
If you do experience side effects, a reduction in dose may minimise these so that you can continue to take the medicine. Your doctor will advise on any dose changes that are necessary.
There are some rare but potentially serious side effects with allopurinol.
Allopurinol can be taken for long periods to manage gout. There seems to be no long-term side effects.
Allopurinol does not affect a person’s ability to have children in the long term. See also Precautions.