Allopurinol tablets

Allopurinol is a prescription-only medicine which belongs to a group of medicines known as xanthine oxidase inhibitors (XOIs). Allopurinol tablets contain the active ingredient allopurinol and are used to lower uric acid levels in the body to help prevent future gout attacks. They are usually prescribed for the long term treatment of gout and to be taken daily. They can help prevent joint damage due to repeated gout attacks.

Allopurinol is changed inside the body to another compound called oxypurinol which works to lower uric acid levels by blocking an enzyme called xanthine oxidase which the body uses to make uric acid. This process reduces uric acid levels in the body and as a result prevents painful symptoms of gout attacks like joint swelling and inflammation.

Gout attacks happen when high uric acid levels in the body become crystals which settle in your joints causing a sudden painful swelling around the joints. This is why people who have gout are advised to manage symptoms with lifestyle changes, painkillers for sudden attacks (short term management) and allopurinol tablets for long term prevention of future gout attacks.

How long does Allopurinol last?

Allopurinol has a half life of about 1-2 hours and it is quickly converted to oxypurinol in the body which lasts longer and works to lower uric acid levels in blood and urine.

How long does Allopurinol take to work?

Allopurinol starts to lower uric acid levels within weeks but it will take months of taking it daily for you to see significant benefits of reduced gout attacks from lower uric acid levels in the body.

How effective is Allopurinol?

Allopurinol is very effective at lowering uric acid levels and preventing gout attack flare ups especially when taken daily and consistently (as a long term treatment). This effectiveness improves when the dosage is gradually increased with the goal to reduce blood uric acid levels to the recommended targets (usually below 360mmol/L).

Allopurinol is the first line treatment recommended by UK guidelines for lowering uric acid levels, with studies like a:

• 2025 meta analysis which found allopurinol to be the ‘best choice to reduce gout flares’ out of a range of randomised controlled trials comparing the effectiveness of different uric acid lowering treatments
• 2014 Cochrane study which compared allopurinol to placebo drugs for chronic gout and found that 96% of patients trialled had achieved target uric acid blood levels, putting them on track for prevention of gout attack flare ups.

You should take Allopurinol tablets as advised by your doctor. You should swallow it whole with a glass of water and take it preferably after food.

If you take more Allopurinol than you should, speak to your doctor or seek urgent medical attention straight away by going to A&E or calling 999. Take your medicine pack with you. Signs of an overdose may include nausea, vomiting, diarrhoea and dizziness.

If you forget to take your Allopurinol dose, take it as soon as you remember it. However, if it is nearly time for the next dose, skip the missed dose. Do not take a double dose to make up a missed dose.

Do not stop taking Allopurinol tablets suddenly without first speaking to your doctor.

When to take Allopurinol

You can take Allopurinol tablets any time during the day but preferably after food to help reduce the risk of side effects like nausea and stomach upset. You should take your tablets around the same time every day to keep the levels of uric acid in your body stable.

You should not start taking Allopurinol when you are having an acute gout attack as it may worsen the symptoms initially. We recommend waiting until your acute gout symptoms have settled before you start Allopurinol.

What’s the best time to take Allopurinol?

You can take Allopurinol tablets any time of the day but preferably after food to reduce the risks of side effects.

How much Allopurinol to take (dosage)

Allopurinol doses can range from 100mg to 900 mg a day. Your doctor will usually start you on the lowest Allopurinol dose of 100mg to be taken once a day. Allopurinol is available at Asda Online Doctor in 100mg and 300mg.

If you are prescribed allopurinol, you will need to have regular blood tests to monitor your uric acid levels. The 100mg dose will be increased if needed and usually after a few weeks, if your uric acids levels are still higher than the target blood levels (usually below 360 mmol/L):

• Mild gout - 100mg to 200mg daily
• Moderate gout - 300mg to 600mg daily
• Severe gout - 700mg to 900mg daily

Doses are usually increased by 100mg at a time and doses above 300mg may be divided across the day to reduce the risk of side effects and maintain steady levels in the body. Your dose may also be lower if you are elderly or have liver and kidney problems.

How long do you need to take Allopurinol for

You will need to take Allopurinol long term to help reduce gout attack flare ups. It will take a few months to see the full benefits but stopping it suddenly will cause your uric acid levels to increase, leading to more frequent gout attacks. Allopurinol is considered safe to take for a long period of time for gout.

What to do when you’re having a gout attack

If you are having an acute gout attack, take the following steps:

• rest and elevate the joint
• apply an ice pack covered in a towel to the affected joint to reduce pain and inflammation
• avoid alcohol and foods rich in purine like red meat and sea food
• drink plenty of water
• if you are already taking Allopurinol, continue taking it at your usual dose daily during the gout attack
• take anti-inflammatory medicines like colchicine (requires a doctor’s prescription) to help reduce pain and inflammation
• if you have fevers, the joint is very hot and you have symptoms of an infection, seek urgent medical review to rule out septic arthritis of the joint

You may experience some side effects when taking Allopurinol tablets but not everyone will get them. If they do not improve or you are struggling with them, speak to your doctor for advice about alternatives.

Common Allopurinol side effects (experienced by up to 1 in 10 people) are:

• skin rash
• increased level of thyroid stimulating hormone in the blood

Uncommon Allopurinol side effects (experienced by up to 1 in 100 people) are:

• feeling sick (nausea) or being sick (vomiting)
• abnormal liver tests
• diarrhoea

Rare Allopurinol side effects (experienced by up to 1 in 1000 people) are:

• liver problems such as liver inflammation
• occasionally may cause blood disorders with symptoms of bruising more, sore throat or other infection symptoms (people with liver or kidney disease are more susceptible). Tell your doctor as soon as possible if this happens
• can affect the lymph nodes
• high temperature
• blood in your urine (haematuria)
• high levels of cholesterol in your blood (hyperlipidaemia)
• a general feeling of being unwell or feeling weak
• weakness, numbness, unsteadiness on your feet, feeling unable to move muscles (paralysis) or loss of consciousness
• headache, dizziness, drowsiness or disturbance of your vision
• chest pain (angina), high blood pressure or a slow pulse
• male infertility or erectile dysfunction
• enlargement of the breasts, in men as well as women
• a change in your normal bowel habit
• a change in taste
• cataracts
• hair loss or discolouration
• depression
• lack of voluntary coordination of muscle movements (ataxia)
• sensation of tingling, tickling, pricking or burning of skin (paraesthesia)
• build up of fluid leading to swelling (oedema) particularly of your ankles
• abnormal glucose metabolism (diabetes)

Not known (cannot be estimated from available data) Allopurinol side effects include:

• Lichenoid skin rash (itchy reddish-purple skin rash and/or threadlike white-grey lines on mucous membranes)
• Aseptic meningitis (inflammation of the membranes that surround the brain and spinal cord): symptoms include neck stiffness, headache, nausea, fever or consciousness clouding. Seek medical attention immediately if these occur.

If you experience any of the following signs of Allopurinol hypersensitivity (allergic) reaction, stop taking it immediately and seek urgent medical review:

Uncommon (may affect less than 1 in 100 people)

• flaking skin, boils or sore lips and mouth
• very rarely signs may include sudden wheeziness, fluttering or tightness in the chest and collapse

Rare (may affect less than 1 in 1,000 people)

• aching muscles (flu-like symptoms) and generally feeling unwell, fever and chills, headache,
• serious fever, skin rash, joint pain, and abnormalities in blood and liver function tests (these may be signs of a multi-organ sensitivity disorder)
• bleeding in the lips, eyes, mouth, nose or genitals
• any changes to your skin like ulcers of the mouth, throat, nose, genitals, conjunctivitis (red and swollen eyes), widespread blisters or peeling

Very rare (may affect up to 1 in 10,000 people)

• serious allergic reaction which causes swelling of the face or throat
• serious potentially life-threatening allergic reaction

➤ The full list of known Allopurinol side effects can be found in the patient information leaflet included with your medication pack.

How long do Allopurinol side effects last

Allopurinol is a long term medication so it may take a few weeks for your body to adjust and for side effects to improve. If you notice a worsening skin rash especially within the first 6-8 weeks speak to your doctor as soon as possible.

Your gout flare ups may also increase in the first few weeks/months of taking allopurinol so your doctor would usually advise you to take anti-inflammatory medications like colchicine to help with the pain and inflammation.

What to do if you get Allopurinol side effects

You can try a few things at home to help manage mild Allopurinol side effects, for:

• nausea (feeling sick) – eat plain foods and avoid food triggers like spicy, greasy foods
• feeling tired or dizzy – stop and sit or lie down and rest until you feel better, avoid drinking alcohol
• diarrhoea – hydrate and rest, you should speak to your doctor if there is no improvement after a few days

Speak to your doctor if you are unable to manage any side effects at home or if they begin to get worse or start affecting your day-to-day life.

Are there long-term side effects of Allopurinol use?

Allopurinol generally has few side effects and is considered safe to take long term. If you develop kidney or liver disease while taking allopurinol, speak to your doctor for advice about adjusting your allopurinol dosage.

Allopurinol may not be right for everyone. Certain medical conditions or medications can interact with Allopurinol making it less effective, or potentially unsafe.

Tell your doctor before taking allopurinol if you:

• currently have an attack of gout
• have ever had an allergic reaction to allopurinol or any of its other ingredients
• are of Han Chinese, Thai or Korean origin
• have problems with your liver or kidneys
• have thyroid problems
• have heart problems or high blood pressure and you take diuretics and/or a group of medicines called ACE-inhibitors (ramipril or lisinopril)
• are pregnant or breastfeeding

You should always tell your doctor about any medications you are currently taking before starting Allopurinol tablets, including any herbal or over-the-counter medications. Before taking Allopurinol, tell your doctor if you are taking any of the following medications:

• aspirin
• theophylline, used for breathing problems
• medicines used for fits (epilepsy), phenytoin
• vidarabine, used to treat herpes or chickenpox
• antibiotics (ampicillin or amoxicillin)
• didanosine, used to treat HIV infection
• medicines used for cancer
• medicines used to reduce your immune response (immunosuppressants)
• medicines used to treat diabetes
• medicines for heart problems or high blood pressure such as ACE inhibitors or water tablets (diuretics)
• medicines used to thin your blood (anticoagulants), such as warfarin
• any other medicine to treat gout
• 6-Mercaptopurine (used to treat blood cancer)
• azathioprine (used to suppress the immune system)

➤ The full list of known Allopurinol warnings and medication interactions can be found in the patient information leaflet included with your medicine pack.

Allopurinol tablets are available via prescription from online doctor services like Asda Online Doctor. You may also be able to get them through your local GP if suitable for you, but you would first need a face to face consultation.

Can I buy Allopurinol online?

Yes. Allopurinol 100mg and 300mg tablets are available to request online at Asda Online Doctor as a prescription-only medication. To request Allopurinol tablets:

1. Fill in a quick online health questionnaire.
2. One of our doctors will review your request to assess your suitability.
3. If your request is approved you can collect Allopurinol tablets from your local Asda Pharmacy or get it delivered to your door.
4. If your request is not approved, one of our doctors may recommend an alternative treatment.

Can I buy Allopurinol over the counter?

No, you cannot buy Allopurinol over the counter. It requires a doctor’s prescription, so a doctor needs to first check if it is suitable and safe for you before giving you a prescription.

Can I get Allopurinol on the NHS?

Yes, you may be able to get Allopurinol on the NHS, usually through your local GP. You will need to book an appointment with your GP first to check if it is safe and suitable for you.

If Allopurinol tablets are not suitable or have not worked effectively for you, there are alternative uric acid lowering medicines to help prevent future gout attacks. They include:

• Febuxostat - also a xanthine oxidase inhibitor like allopurinol, this is typically prescribed if you are not tolerating allopurinol or if you have poor kidney function
• Specialist initiated medications like probenecid or benzbromarone, which increase uric acid excretion via kidneys

There are other treatment options for acute gout flare ups which work to reduce pain and inflammation around the affected joints. These are:

• Colchicine
• NSAIDs like ibuprofen or naproxen
• Oral steroids - usually a short course dose for 3-5 days

Allopurinol vs Colchicine

Allopurinol and Colchicine are different medicines prescribed to manage gout for different reasons.

Allopurinol works to lower the amount of uric acid in the body over time by blocking an enzyme the body needs to create uric acid, this helps to prevent further flare ups. On the other-hand, colchicine works by reducing inflammation and pain around the affected joint during acute gout attacks. Therefore, allopurinol is mainly used for long-term treatment of gout, whereas colchicine focuses on short-term relief during gout attacks.

If you are starting Allopurinol for the first time, you may experience increased gout attacks initially based on how the medicine works. To help manage this, your doctor will also prescribe a lower dose of colchicine or an NSAID to take daily for a few months, until your symptoms settle and you achieve the target uric acid blood level.

Here is a brief comparison table of Allopurinol vs Colchicine:

Asda Online Doctor also offers a Gout Test Kit which checks for high uric acid levels in your blood, allowing you to get treatment if needed. It is a home test kit so you can take it in the comfort of your home.

If you think you’re at risk of getting gout, or you want to check your uric acid levels to make sure your treatment is working, you can request your Gout Test Kit from Asda Online Doctor.

Does Allopurinol worsen acute gout?

In the long term, Allopurinol does not worsen gout but it can trigger gout flare ups when you first start taking it, as your body works to reduce blood uric acid levels and the joint crystals.

Can you take Allopurinol and Colchicine together for gout?

Yes, your doctor will usually prescribe both Allopurinol and a lower dose of colchicine or an NSAID to take daily for a few months, until your symptoms settle and you achieve the target uric acid blood level.

Can you take Ibuprofen with Allopurinol for gout?

Yes, your doctor may prescribe an NSAID like ibuprofen or a lower colchicine dose to help manage acute gout flare ups which may become more frequent initially when you start taking Allopurinol.

Can I drink alcohol while taking Allopurinol tablets?

Although there are no known interactions between allopurinol and drinking alcohol, alcohol can cause high uric acid levels in the blood which can worsen gout attacks. It is advisable to avoid or reduce your alcohol intake if you have gout.

Does Allopurinol cause weight gain?

There is no known direct link between taking Allopurinol and weight gain, although fluid retention is listed as a rare Allopurinol side effect.

Is Allopurinol safe to take long-term?

Allopurinol is considered safe to take long term. If you develop kidney or liver disease while taking Allopurinol, speak to your doctor for advice about adjusting your dosage.

What should I avoid when taking Allopurinol?

To reduce your risk of future gout attack flare ups, you should aim to avoid the following when taking Allopurinol:

• red meat, kidneys, liver, or seafood
• sugary drinks and snacks
• fatty foods
• alcohol