Allopurinol lowers the amount of uric acid in your blood.
It's also known by the brand names Alopur, Tipuric and Zyloric.
You can only get allopurinol on prescription. It comes as tablets.
Allopurinol is for adults. It is very rarely given to children.
Uses for allopurinol
Allopurinol is used to treat gout and kidney stones.
You might also have to take allopurinol if you are getting some types of cancer treatment. Some treatments can cause a build up of uric acid.
You can help stop or reduce attacks of gout by making lifestyle changes while taking allopurinol.
Check if you can take allopurinol
Contact your GP before you take allopurinol if you:
- have had an allergic reaction to any medicine
- are pregnant or breastfeeding
- have an existing health problem
- are taking other medicines, including herbal medicines, vitamins or supplements
- are of Han Chinese, Thai or Korean origin
Talk to your GP or pharmacist before taking allopurinol if you:
- are pregnant
- think you might be pregnant
- are trying to have a baby
Pregnancy and allopurinol
Allopurinol is usually not recommended during pregnancy. There is not enough evidence to say that it's safe.
Breastfeeding and allopurinol
Allopurinol passes into breast milk.
Talk to your GP or pharmacist before taking allopurinol if you are breastfeeding.
If you have an existing health problem
Allopurinol is not suitable for some people.
Check with your GP before you start to take allopurinol if:
- you have ever had an allergic reaction to allopurinol or any other medicines
- you're having liver, thyroid or kidney problems
- are currently having a gout attack
Dosage
Your GP will usually start you on a low dose of allopurinol.
You'll have regular blood tests to monitor your uric acid levels.
Your GP may increase or decrease your dose depending on the results of your blood tests.
When to take allopurinol
Always take allopurinol exactly as your GP has told you. Check with your GP, pharmacist or nurse if you are not sure.
Usually, you'll take allopurinol once a day after a meal. Swallow the tablets with a little water.
Drink 2 to 3 litres of fluids a day while you are taking allopurinol.
Keep taking allopurinol even when you no longer have symptoms.
How long it takes to work
Usually it takes several months to feel the full benefits of allopurinol.
When allopurinol is taken regularly, it can lower how many gout attacks you have and help prevent damage to your joints.
How long you need to take allopurinol
Treatment with allopurinol is usually lifelong. If you stop taking it your symptoms are likely to come back.
Do not stop taking allopurinol unless your GP tells you to. If you stop allopurinol treatment suddenly, there is a high risk that gout may get worse or you'll get serious side effects.
Talk to your GP first if you want to stop taking allopurinol.
If you forget to take it
If you forget to take your dose, take it as soon as you remember.
Skip the forgotten dose if it’s almost time for your next dose.
Never take 2 doses at the same time. Never have an extra dose to make up for a forgotten one.
Use an alarm to help remind you to take your doses. Ask your pharmacist for advice if you forget doses often.
If you take too much
Emergency action required: Contact your GP straight away or go to your nearest emergency department (ED) if:
- you take too many tablets
Bring the allopurinol packet or leaflet and any remaining medicine with you.
Side effects of allopurinol
Allopurinol can cause side effects, although not everyone gets them.
The most common side effect of allopurinol is:
Feeling or getting sick (nausea or vomiting)
If you're feeling sick, eat little and often and drink lots of fluids. Try taking your medicine with food or just after you eat. Stick to simple meals and do not eat rich or spicy food.
If you're getting sick, take small, frequent sips of water to avoid dehydration. Signs of dehydration include peeing less than usual or having dark, strong-smelling pee.
If you take contraceptive pills and you're being sick, your contraception may not protect you from pregnancy. Check the pill packet for advice.
Serious side effects
It's unusual to have serious side effects after taking allopurinol.
But serious side effects can include:
- stomach pain or bruising
- Stevens-Johnson syndrome - this is rare
Urgent advice: Ask for an urgent GP appointment if you:
- have severe stomach pain or the whites of your eyes or your skin turn yellow - these can be signs of liver problems
- are bruising more easily than usual
- have a sore throat or other signs of an infection
Serious allergic reaction
Serious allergic reactions (anaphylaxis) to allopurinol are very rare.
Urgent advice: Contact your GP straight away if:
- you get a rash that may include itchy, red, swollen, blistered or peeling skin
- you're wheezing
- you have tightness in the chest or throat
- you have trouble breathing or talking
- your mouth, face, lips, tongue or throat start swelling
- you have a high temperature of 38 degrees Celsius or higher along with a headache, aching muscles and generally feel unwell
- you have bleeding in the lips, eyes, mouth, nose or genitals
- you have ulcers of the mouth, throat, nose, genitals and conjunctivitis
Do not take any more tablets unless your GP tells you to.
See the patient information leaflet that comes with your medicine for a full list of side effects.
Non-urgent advice: Find your patient information leaflet
Your patient information leaflet is the leaflet that comes with your medicine. You can find a digital version of the leaflet online.
Report side effects
You can report any suspected side effects to the Health Products Regulatory Authority (HPRA): report an issue - hpra.ie
Driving or cycling and allopurinol
Allopurinol may make some people drowsy or have problems with their coordination.
Do not drive, cycle or operate machinery if these symptoms affect you.
Taking allopurinol with other medicines
Tell your GP or pharmacist that you are on allopurinol before taking any other medicines.
It's especially important that you check this with your GP if you are taking:
- blood thinners such as warfarin
- any antibiotics
- medicines used to lower your immune response (for arthritis or after you've had an organ transplant)
- tablets that make you pee more (diuretics), such as furosemide
- ACE inhibitors to treat high blood pressure (hypertension), such as enalapril or ramipril
Do not take an antacid or aluminium hydroxide with allopurinol without talking to your GP first.
If you take aluminium hydroxide (found in some antacids such as Maalox), leave a 3-hour gap between the aluminium hydroxide and your allopurinol dose.
Herbal remedies and supplements
Tell your pharmacist or GP if you're taking herbal remedies, vitamins or supplements.
Painkillers
It's safe to take painkillers such as paracetamol or ibuprofen at the same time as allopurinol.
To help prevent or deal with gout attacks, your doctor may prescribe:
- an NSAID
- a medicine called colchicine
Alcohol and allopurinol
You can drink alcohol while taking allopurinol. But alcohol increases the level of uric acid in your blood. This can trigger an attack of gout or make it worse.
Fact check
This content was fact checked by a pharmacist, a GP, and the National Medication Safety Programme (Safermeds).
