Allopurinol is prescribed to help prevent gout attacks. It does not have any effect during a gout attack, although you should continue to take it regularly every day, even if this happens. A painkilling medicine will be prescribed for you to take alongside it should you get a gout attack.
Take allopurinol tablets with a glassful of water, preferably after food.
Allopurinol can cause a skin rash. Although most rashes are mild, you must let your doctor know as soon as possible if this happens to you.
|Type of medicine||A xanthine-oxidase inhibitor|
|Used for||To prevent attacks of gout; to reduce high blood levels of uric acid associated with some types of kidney stones and cancer treatments|
|Also called||Uricto®; Zyloric®|
Gout causes attacks of painful inflammation in one or more of your joints. It is caused by a build-up of a naturally occurring chemical in your blood, called uric acid (urate). From time to time, the level of uric acid in your blood may become too high and tiny grit-like crystals may form, which typically collect in your joints and tendons. The crystals irritate the tissues of the joint to cause inflammation, swelling, and pain.
If you have had a number of gout attacks, your doctor will advise that you take a medicine every day to help prevent more attacks from occurring. Allopurinol is the medicine which is most commonly prescribed for this. It helps to prevent gout attacks by reducing the levels of uric acid in your blood. As it is not a painkiller, it does not have any effect during a gout attack, so you will still need to take pain relief should you have any further attacks. In this case, your doctor will prescribe either an anti-inflammatory painkiller or colchicine for you to take alongside allopurinol.
Allopurinol can also help prevent uric acid levels building up in some other conditions too. These include some types of kidney stones, and during some treatments for cancer. It works in these conditions by lowering the levels of uric acid in blood.
Before taking allopurinol
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 allopurinol it is important that your doctor knows:
- If you are pregnant or breastfeeding.
- If you have any problems with the way your liver works, or any problems with the way your kidneys work.
- If you have an overactive or underactive thyroid gland.
- If you are taking or using any other medicines. This includes any medicines you are taking which are available to buy without a prescription, as well as herbal and complementary medicines.
- If you have ever had an allergic reaction to a medicine.
How to take allopurinol
- Before you start the treatment, read the manufacturer's printed information leaflet from inside the pack. It will give you more information about allopurinol and will provide you with a full list of the side-effects which you may experience from taking it.
- If you have recently had a gout attack, make sure your symptoms have completely gone before you start taking allopurinol tablets.
- Take allopurinol exactly as your doctor tells you to. The usual starting dose is one tablet (100 mg) each day, although this may be increased as you go on. Your dose will be adjusted in line with how much uric acid is in your blood.
- Swallow the tablet with a full glass of water, preferably just after a meal. It's also important that you have plenty to drink throughout the day. Aim to drink 2-3 litres of fluid each day.
- You can take allopurinol at whatever time of day you find easiest to remember; however try to take your doses at the same time of day each day, as this will help you to take it regularly.
- If you forget to take a dose, take it as soon as you remember. If you do not remember until the following day, skip the forgotten dose. Do not take two doses at the same time to make up for a missed dose.
Getting the most from your treatment
- Try to keep your regular appointments with your doctor. This is so your doctor can check on your progress. Your doctor will want you to have a blood test to check that the level of uric acid has come down. This is often done a month or so after starting allopurinol.
- Remember, allopurinol should be taken every day to prevent a gout attack. It can take 2-3 months to become fully effective. It does not have any effect during a gout attack, although you should continue to take it regularly every day even if this happens.
- During the first few weeks of taking allopurinol, your blood levels of uric acid may rise for a short while before they fall. This can cause a gout attack. Your doctor will prescribe an anti-inflammatory treatment or colchicine tablets for you to take alongside allopurinol during this time.
- Treatment with allopurinol is usually long-term unless you experience an adverse effect. Continue to take the tablets unless you are advised otherwise by a doctor.
- There are a number of lifestyle changes that you can make to help reduce the risk of having a gout attack. These include losing weight (if you are overweight), eating a healthy diet and not drinking much alcohol or sugar-sweetened soft drinks. Your doctor will advise you about the changes which could benefit you.
Can allopurinol cause problems?
Along with their useful effects, most medicines can cause unwanted side-effects although not everyone experiences them. The table below contains some of the most common ones associated with allopurinol. 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.
|Common allopurinol side-effects (these affect less than 1 in 10 people)||What can I do if I experience this?|
|Skin rash (this can occur at any time during treatment with allopurinol)||You should let your doctor know about this (even if the rash is mild) as it could be an allergic-type reaction|
|Changes to blood levels of thyroid stimulating hormone (TSH)||Your doctor will check for this|
If you experience any other symptoms which you think may be due to the tablets, speak with your doctor or pharmacist for further advice.
How to store allopurinol
- Keep all medicines out of the reach and sight of children.
- Store in a cool, dry place, away from direct heat and light.
Important information about all medicines
Never take more than the prescribed dose. If you suspect that you or someone else might have taken an overdose of this medicine, go to the accident and emergency department of your local hospital. Take the container with you, even if it is empty.
This medicine is for you. Never give it to other people even if their condition appears to be the same as yours.
If you buy any medicines 'over the counter', always check with a pharmacist that they are suitable for you to take alongside your other medicines.
If you are having an operation or any dental treatment, tell the person carrying out the treatment which medicines you are taking.
Do not keep out-of-date or unwanted medicines. Take them to your local pharmacy which will dispose of them for you.
If you have any questions about this medicine ask your pharmacist.
Further reading and references
; Aspen, The electronic Medicines Compendium. Dated December 2017.
British National Formulary, 75th Edition (Mar 2018); British Medical Association and Royal Pharmaceutical Society of Great Britain, London.