Allopurinol

Sounds like 'al-lo-pew-ri-nol'

Key points about allopurinol

  • Allopurinol is a long-term treatment to prevent gout attacks.
  • It helps to prevent permanent damage to your joints.
  • It's important to keep taking allopurinol every day — it may take several months before you feel the full benefit of allopurinol.
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Allopurinol is used mainly as a long-term daily treatment to prevent gout attacks or flares. It helps to prevent permanent damage to your joints.

Allopurinol can also be used to prevent some types of kidney stones and may be used in people receiving cancer chemotherapy, to prevent high uric acid that can occur with some types of chemotherapy.

  • Allopurinol reduces the amount of uric acid your body makes. Uric acid is produced in your body when you digest and metabolise some types of food and drinks.
  • Usually excess uric acid is passed out in urine, but when uric acid levels are too high, crystals can form around joints causing inflammation, pain and damage. This is known as gout. 
  • The crystals can also cause lumps under your skin called tophi.

Checking your uric acid levels

  • Uric acid levels can be checked with a blood test, either at your clinic or pharmacy.
  • To reduce gout attacks, it's important to keep your uric acid level is below 0.36 mmol/L.
  • When your uric acid is below 0.36mmol/L no new crystals form and crystals that are in your joints can dissolve.
  • If you have tophi, the goal is to get to a uric acid level below 0.3 mmol/L.


Video: Deciding to take allopurinol for gout

(Health Navigator Charitable Trust, NZ, 2023)

 

Video: Starting on allopurinol for gout


(Health Navigator Charitable Trust, NZ, 2023)

In Aotearoa New Zealand allopurinol is available as 100 mg and 300 mg tablets.

  • The dose of allopurinol will be different for different people.
  • Your doctor will usually start you on a low dose (50 or 100 mg each day) and increase it very slowly over a few months.
  • Your doctor will measure your uric acid level with a blood test and increase the allopurinol dose as much as needed until your uric acid level is less than 0.36 mmol/L. 
  • This may take 6 to 12 months of taking allopurinol every day.
  • The usual dose of allopurinol is 100 to 600 mg a day. Some people may need up to 900 mg daily. 
  • Always take your allopurinol exactly as your doctor has told you. The pharmacy label on your medicine will tell you how much to take, how often to take it, and any special instructions. Know what dose you should be taking - if you are unsure, talk to your pharmacist.

You can use the following plan to help keep track of your allopurinol as you increase your daily dose.

My dose is:

Week Dose
week beginning:   
week beginning:   
week beginning:   
week beginning: 
 
Notes:



  • Timing: Take allopurinol once a day with a full glass of water. If you think allopurinol is causing stomach upset, try taking it with food. If you are taking more than 300 mg per day, you may wish to take it twice a day. Talk to your doctor about this
  • Drink plenty of water: It's important to drink plenty of water while you're taking allopurinol because kidney stones can develop if you don't drink enough fluid.
  • Limit or avoid alcohol while you are taking allopurinol: Alcohol can trigger an attack of gout. 
  • Missed dose: If you forget to take your dose of allopurinol, take it as soon as you remember. But if it is nearly time for your next dose, just take the next dose at the right time. Don't take double the dose.
  • Keep taking allopurinol every day, even during a gout attack: Allopurinol takes 2 to 3 months to become fully effective. Don't stop taking allopurinol suddenly; talk to your doctor or nurse before stopping. Allopurinol is a long-term medicine – you'll probably need to take allopurinol for the rest of your life. Stopping allopurinol quickly can make your gout worse.

When you first start allopurinol, you may get an upset stomach and nausea (feeling sick). Taking your dose with food helps to ease these symptoms.

Increased gout attacks or flare ups: You may have gout attacks or flare-ups in the first few weeks or months as you're increasing your dose of allopurinol.

  • Your doctor will prescribe additional medication (eg, a low-dose non-steroidal anti-inflammatory (NSAID) or colchicine)  to reduce the chances of an attack during this time.
  • Keep taking allopurinol every day, even during a gout attack.
  • As your uric acid level decreases over time you're less likely to get gout attacks.
  • Keeping your uric acid level below 0.36 mmol/l, will help stop your gout attacks. This may take 6 to 12 months of taking allopurinol every day.

Blood tests: When you first start taking allopurinol, you'll need to have blood tests to monitor your uric acid levels every 4 weeks until the target level has been reached. Then you'll need blood tests every 3 to 6 months to check your uric acid level and your kidney function.

Here are some things to know when you're taking allopurinol. Other things may be important as well, so ask your healthcare provider what you should know about.

  • Skin rash: You may get a skin rash or itching (about 2 in every 100 people who take allopurinol will have a skin rash). This can happen anytime while taking allopurinol, but especially in the first few months while your dose is being increased. If this happens, stop taking allopurinol and contact your doctor immediately – even if the rash is mild. This can develop into a severe allergic reaction.
  • Other medicines: Allopurinol may interact with other some other medicines, herbal supplements and rongoā Māori, so check with your doctor or pharmacist before starting allopurinol and before starting any new products.
  • If I am having a gout attack, will an extra dose help? No. Allopurinol is not a pain reliever and doesn't start working immediately. If you have an attack of gout while taking allopurinol, keep taking it at the same dose. Don't stop taking it. Your doctor will advise you to take a pain reliever medicine, eg, NSAIDs (ibuprofen, diclofenac, naproxen), or steroid, eg, prednisone or colchicine. You can also apply ice-packs and rest the affected joint to reduce pain. See your doctor if the pain and inflammation doesn't improve in 24 hours.
  • What if allopurinol doesn't help? After starting allopurinol, your doctor will monitor your symptoms and your uric acid levels. If after a few months of being on an optimal dose of allopurinol, your symptoms don't improve and your uric acid levels remain high, your doctor may try you on other medicines (eg, febuxostat, probenecid or benzbromarone).

Like all medicines, allopurinol can cause side effects, although not everyone gets them. Often side effects improve as your body gets used to the new medicine.

Side effects What should I do?
  • Skin rash or itching
    (about 2 in every 100 people who take allopurinol will have a skin rash)
  • Stop taking allopurinol
  • Contact your doctor immediately – even if the rash is mild. This can develop into a severe allergic reaction.
  • Stomach upset, nausea (feeling sick), or vomiting
  • This is quite common when you first start taking allopurinol.
  • Try taking allopurinol with food or milk.
  • If it gets worse, contact your doctor.  
  • Muscle pain
  • Dizziness, drowsiness
  • Tell your doctor if these bother you. 
Did you know that you can report a medicine side effect to CARM (Centre for Adverse Reactions Monitoring)? Report a side effect to a product.(external link)

Brochures

allopurinol maori

medicine for gout info sheet

Medicines for gout

Medsafe and Ministry of Health, NZ

English
Te reo Māori
Samoan

5 questions to ask about your medications

5 questions to ask about your medications

Health Quality and Safety Commission, NZ, 2019

English
Te reo Māori

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Credits: Sandra Ponen, Pharmacist, Healthify He Puna Waiora. Healthify is brought to you by Health Navigator Charitable Trust.

Reviewed by: Angela Lambie, Pharmacist, Auckland.

Last reviewed: