Allopurinol tablets 100 mg – patient leaflet, side effects, dosage

1. WHAT ALLOPURINOL TABLETS ARE AND WHAT THEY ARE USED FOR

Allopurinol Tablets contain a medicine called allopurinol. It works by slowing down the speed of certain chemical reactions in your body.

Allopurinol Tablets are used:-

! To prevent gout. This is a disease where

your body produces too much of a substance called 'uric acid'. The uric acid builds up in your joints and tendons and forms crystals. These cause an

inflammatory reaction. The inflammation causes the skin around certain joints to become swollen, tender and sore when only slightly touched. Severe pain may also be felt on slight movement of the joint ! To prevent other conditions where there is a

build up of uric acid in the body. This includes kidney stones.

2. WHAT YOU NEED TO KNOW BEFORE YOU TAKE ALLOPURINOL TABLETS

Do not take Allopurinol Tablets if you:

! Are hypersensitive to

allopurinol or any of the other ingredients of this medicine (listed in section 6).

Warnings and precautions

Talk to your doctor, pharmacist or nurse before taking Allopurinol Tablets if you:

! Have liver or kidney problems. Your doctor may give you a lower dose or ask you to take it less often each day. You will also be monitored more closely ! Have heart problems or high blood pressure

and you take diuretics and/or a medicine called ACE inhibitors

! Have been told by your doctor that you

have an intolerance to some sugars as this medicine contains lactose

! Are currently having an attack of gout ! You have thyroid problems

! You are of Han Chinese, African or Indian

origin.

Serious skin rashes (hypersensitivity syndrome, Stevens- Johnson syndrome, toxic epidermal necrolysis) have been reported with the use of allopurinol.

Frequently, the rash can involve ulcers of the mouth, throat, nose, genitals and conjunctivitis (red and swollen eyes). These serious skin rashes are often preceded by influenza like symptoms, fever, headache, body ache (flu-like symptoms). The rash may progress to widespread blistering and peeling of the skin.

These serious skin reactions can be more common in people of Han Chinese, Thai or Korean origin. Chronic kidney disease may increase the risk in these patients additionally. If you develop a rash or these skin symptoms, stop taking allopurinol and contact your doctor immediately.

If you have cancer or Lesch-Nyhan syndrome the amount of uric acid may increase in your urine. To prevent this, you need to assure to drink sufficiently to dilute your urine.

In case you have kidney stones, the kidney stones will become smaller and may enter your urinary tract.

Children and adolescents

Use in children is rarely indicated, except in some types of cancer (especially leukaemia) and certain enzyme disorders such as Lesch-Nyhan syndrome.

Allopurinol Tablets 100mg Allopurinol Tablets 300mg

PACKAGE LEAFLET: INFORMATION FOR THE USER

Other medicines and Allopurinol Tablets

Tell your doctor or pharmacist if you are taking, have recently taken or might take any other medicines.

It is especially important to tell your doctor if you are taking any of the medicines listed below. Your doctor may need to reduce the dose of your medicine and/or monitor you more carefully because of the increased risk of side effects when Allopurinol Tablets are taken at the same time as:

! Azathioprine (used to suppress the immune

system)

! Ciclosporin (to treat psoriasis, rheumatoid

arthritis or after organ transplants) ! 6-mercaptopurine (used to treat some

cancers and bowel diseases)

! Cyclophosphamide, doxorubicin, bleomycin

or procarbazine (drugs used to treat leukaemias and some cancers) ! Probenecid (used in gout)

! Phenytoin (used in epilepsy)

! Theophylline (to treat asthma)

! Ampicillin or amoxicillin (antibiotics) ! Aspirin or related medicines (salicylates) ! Drugs to prevent blood from clotting (such

as warfarin)

! Chlorpropamide (used in diabetes) ! Didanosine (antiviral)

! Diuretics (water tablets) or ACE inhibitors

such as captopril (used in high blood pressure)

! Vidarabine, used to treat herpes or

chickenpox.

The co-administration of 6-mercaptopurine or azathioprine with allopurinol should be avoided. When 6-mercaptopurine or azathioprine is given concurrently with Allopurinol Tablets, the dose of 6-mercaptopurine or azathioprine should be reduced because their activity will be prolonged. This could increase the risk of serious blood disorders. In this

case, your doctor will closely

monitor your blood count during

treatment.

Seek medical advice immediately

if you notice that you have any

unexplained bruising, bleeding,

fever or sore throat.

If aluminium hydroxide is taken

concomitantly, allopurinol may

have an attenuated effect. There

should be an interval of at least 3

hours between taking both medicines.

With administration of allopurinol and cytostatics (e.g. cyclophosphamide, doxorubicin, bleomycin, procarbazine, alkyl halogenides), blood dyscrasias occur more frequently than when these active substances are administered alone.

Blood count monitoring should therefore be performed at regular intervals.

Pregnancy and breast-feeding

Ask your doctor or pharmacist for advice if you are pregnant, planning on becoming pregnant or are breast-feeding. Please check with your doctor if you are taking these tablets and want to breast-feed your baby. Allopurinol is excreted in the human breast milk. Allopurinol during breastfeeding is not recommended.

Driving and using machines

These tablets can cause some people to feel drowsy, giddy or have problems with co-ordination. If you are affected do not drive or operate machinery as your alertness may be impaired.

Allopurinol Tablets contain lactose

Allopurinol Tablets contain lactose. If you have been told by your doctor that you have an intolerance to some sugars, contact your doctor before taking this medicinal product.

Allopurinol Tablets 300mg contain sodium

This medicine contains less that 1 mmol sodium (23 mg) per tablet, that is to say essentially 'sodium-free'.

3. HOW TO TAKE ALLOPURINOL TABLETS

Always take Allopurinol Tablets exactly as your doctor has told you. Check with your doctor or pharmacist if you are unsure.

Swallow the tablet with a drink of water Take with or just after food.

Your doctor will usually start with a low dose of allopurinol (e.g. 100 mg/day), to reduce the risk of possible side effects. Your dose will be increased if necessary.

Adults:

The usual starting dose is 100 to 200mg each day. Your doctor will monitor the uric acid levels in your blood or urine at regular intervals and will adjust the dose to suit you as necessary. The maintenance dose is usually 200mg to 600mg daily. The maximum single dose is 300mg. It is unlikely that you will be prescribed more than 900mg per day.

Use in children and adolescents:

The dose in children is based on 10mg to 20mg/kg of body weight/day up to a maximum of 400mg daily. Your doctor will prescribe the correct dosage. Use in children is mainly for certain types of cancers and enzyme disorders.

Elderly patients:

Your doctor will prescribe the lowest dose of Allopurinol Tablets that best controls your symptoms.

Patients with severe kidney problems:

You may be asked to take less than 100mg a day, or you may be asked to take 100mg at a longer interval than each day. The exact dose will be prescribed by your doctor.

If you are receiving kidney dialysis two or three times a week, your doctor may prescribe a dose of 300 or 400mg which will be to take straight away after your dialysis.

Patients with liver problems:

A reduced dose will be prescribed by your doctor.

If you take more Allopurinol Tablets than you should

If you take too many tablets by mistake contact your nearest hospital casualty department or tell your doctor immediately. Take your tablet pack with you.

If you stop taking Allopurinol Tablets

Do not stop taking Allopurinol Tablets without consulting your doctor.

If you forget to take Allopurinol Tablets

If you have forgotten to take a dose, take it as soon as you remember it. However, if it is almost time to take your next dose, skip the missed dose. Do not take a double dose to make up for a forgotten dose. If you have trouble remembering to take the tablets, tell your doctor or pharmacist.

If you have any further questions on the use of this medicine, ask your doctor or pharmacist.

4. POSSIBLE SIDE EFFECTS

Like all medicines, this medicine can cause side effects, although not everyone gets them.

The following side effects may happen with this medicine: Hypersensitivity

Uncommon (may affect up to 1 in 100 people):

If you have a hypersensitivity (allergic) reaction, stop

taking Allopurinol and see a doctor straight way. The signs may include:

! 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 up to 1 in 1,000 people): ! serious hypersensitivity reactions including

? fever, joint pain, abnormalities in blood

and liver function tests (these may be signs of a multi-organ sensitivity disorder) ? fever and chills, headache, aching

muscles (flu like symptoms) and generally feeling unwell

? any changes to your skin, for example

ulcers of the mouth, throat, nose, genitals and conjunctivitis (red and swollen eyes), widespread blisters or peeling

? bleeding in the lips, eyes, mouth, nose or

genitals.

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

Do not take any more tablets unless your doctor tells you to do so.

Other side effects

Common (may affect up to 1 in 10 people): ! skin rash

! increased level of thyroid stimulating

hormone in the blood.

Uncommon (may affect up to 1 in 100 people): ! feeling or being sick (occasionally with blood) ! changes in liver function tests

! diarrhoea.

Rare (may affect up to 1 in 1,000 people)

! liver problems such as liver inflammation.

Very rare (may affect up to 1 in 10,000 people): ! occasionally Allopurinol Tablets may affect

your blood, which can manifest as bruising more easily than usual, or you may develop a sore throat or other signs of an infection. These effects usually occur in people with liver or kidney problems. Tell your doctor as soon as possible.

! Allopurinol Tablets may affect the Lymph

Nodes

! weakness, numbness, 'pins and needles',

'spinning' sensation, unable to move muscles ( p a r a l y s i s ) , d r o w s i n e s s , l o s s o f consciousness

! feeling thirsty, tired and losing weight; these

may be signs of diabetes, taste changes, build up of fluid leading to swelling (oedema) particularly of your ankles

! high levels of cholesterol in the blood

(hyperlipidaemia)

! depression

! hair loss or discolouration

! cataracts, changes in vision

! blood in the urine (haematuria), a change in bowel habit

! high temperature, a general feeling of being unwell, headache, dizziness

! high blood pressure

! enlarged breasts in men and women, difficulty maintaining erection, infertility ! chest pain (angina) or slow pulse

! lack of voluntary coordination of muscle movements (ataxia)

! sensation of tingling, prickling or burning skin

(paraesthesia)

! abnormal glucose metabolism (diabetes).

Your doctor may wish to measure the level of sugar in your blood to check if this is happening

! occasionally Allopurinol tablets may affect your blood, which can manifest as bruising more easily than usual, or you may develop a sore throat or other signs of an infection. These effects usually occur in people with liver or kidney problems. Tell your doctor as soon as possible.

Not known (frequency cannot be estimated from the available data):

! 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 ! Lichenoid skin rash (itchy reddish-purple skin rash and/or threadlike white-grey lines on mucous membranes).

If any of the side effects gets serious, or if you notice any side effects not listed in this leaflet, please tell your doctor or pharmacist.

Reporting of side effects

If you get any side effects, talk to your doctor, pharmacist or nurse. This includes any possible side effects not listed in this leaflet. You can also report side effects directly via the Yellow card

Scheme at: www.mhra.gov.uk/yellowcard or search for MHRA Yellow Card in the Google Play or Apple App Store.

By reporting side effects you can help provide more information on the safety of this medicine.

5. HOW TO STORE ALLOPURINOL TABLETS

Keep this medicine out of the sight and reach of children.

Do not use this medicine after the expiry date which is stated on the label. The expiry date refers to the last day of that month.

Blister packs: Do not store above

25°C. Keep the blister in the outer carton to protect from light and moisture.

Securitainers: Store in a cool, dry place and protect from light.

Do not use this medicine if you notice any visible signs of deterioration.

Do not throw away any medicines via waste water or household waste. Ask your pharmacist how to dispose of medicines no longer required. These measures help to protect the environment.

6. CONTENTS OF THE PACK AND OTHER INFORMATION

What Allopurinol Tablets 100mg contain

! 100mg of the active substance Allopurinol ! The other ingredients are lactose, maize starch, povidone and magnesium stearate

What Allopurinol Tablets 300mg contain

! 300mg of the active substance Allopurinol ! The other ingredients are lactose, maize starch, povidone, magnesium stearate and sodium starch glycollate

What Allopurinol Tablets look like and contents of the pack

Allopurinol Tablets 100mg are white, circular biconvex, uncoated tablets, with A1 embossed on one side. Diameter: 9.5mm.

Allopurinol Tablets 300mg are white, circular, biconvex, uncoated tablets, with ‘A’ & ‘2’ debossed on either side of score line on one side and plain on other side. Diameter: 11.00mm.

Allopurinol Tablets 100mg are supplied in packs of 28, 30, 56, 60, 84, 90 or 250 tablets. Allopurinol Tablets 300mg are packed into packs of 28, 30, 56, 60, 84, 90 or 250 tablets.

Marketing Authorisation Holder

Ennogen IP Ltd

Unit G4, Riverside Industrial Estate,

Riverside Way, Dartford, DA1 5BS, UK

Manufacturer

Ennogen Pharma Limited

Unit G4, Riverside Industrial Estate,

Riverside Way, Dartford, DA1 5BS, UK.

This leaflet was last revised in July 2026.

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