• Keep this leaflet. You may need to read it again.
• If you have any further questions, ask your doctor, nurse or pharmacist.
• This medicine has been prescribed for you only. Do not pass it on to others. It may harm them, even if their signs of illness are the same as yours.
• If you get any side effects, talk to your doctor, pharmacist or nurse. This includes any possible side effects not listed in this leaflet. See section 4.

1. What Tioguanine is and what it is used for
2. What you need to know before you take Tioguanine
3. How to take Tioguanine
4. Possible side effects
5. How to store Tioguanine
6. Contents of the pack and other information

if you are allergic (hypersensitive) to tioguanine or any of the other ingredients of this medicine (listed in section 6).

Talk to your doctor, pharmacist or nurse before taking Tioguanine:

• if you have been taking this medicine for a long period of time. This may increase the chance of side effects, such as liver problems
• if you have a condition where your body produces too little of something called TPMT or ‘thiopurine methyltransferase’
• if you have ‘Lesch-Nyhan Syndrome’. This is a rare condition that runs in families caused by a lack of something called HPRT or ‘hypoxanthine-guanine-phosphoribosyltransferase’.

If you are not sure if any of the above apply to you, talk to your doctor, nurse or pharmacist before taking Tioguanine.

If you have an inherited mutation in the NUDT15-gene (a gene which is involved in the break-down of Tioguanine in the body), you have a higher risk of infections and hair loss and your doctor may in this case give you a lower dose. Your doctor may also perform genetic testing (i.e. looking at your TPMT and/or NUDT15 genes) before or during your treatment to determine if your response to this medication may be affected by your genetics. Your doctor may change your dose of Tioguanine after these tests.

Inform your doctor immediately if you experience severe chills, fever, sore throat, cough, flu-like symptoms and headache accompanied by nausea, rash, and/or confusion, while you are taking thioguanine with other cancer treatments as these symptoms may suggest that you have a bacterial, viral or fungal infection which may become severe. Your doctor may prescribe appropriate treatment and other supportive treatments.

While taking Tioguanine you may become sensitive to the sunlight which can cause skin discolouration or a rash. Take care to avoid too much sun, cover up and use sunscreen.

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

In particular tell your doctor or pharmacist if you are taking any of the following:

• olsalzine or mesalazine – used for a bowel problem called ulcerative colitis.
• sulfasalazine – used for rheumatoid arthritis or ulcerative colitis.
• medicines that can have a harmful effect on the bone marrow, like other chemotherapy or radiotherapy. This can lead to bone marrow damage and the dose of Tioguanine may need to be reduced.

If you are going to have a vaccination speak to your doctor or nurse before you have it. This is because some vaccines (like polio, measles, mumps and rubella) may give you an infection if you have them whilst you are taking Tioguanine.

If you are pregnant or are planning to have a baby, ask your doctor for advice before you take Tioguanine. This applies to both men and women. Tioguanine may harm your sperm or eggs. Reliable contraceptive precautions must be taken to avoid pregnancy whilst you or your partner are taking these tablets. If you are breast-feeding, ask your doctor or midwife for advice before taking Tioguanine.

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

If you take more Tioguanine than you should, tell your doctor immediately or go to a hospital straight away. Take the medicine pack with you.

Tell your doctor. Do not take a double dose to make up for a forgotten dose.

• any signs of fever or infection (sore throat, sore mouth or urinary problems).
• any unexpected bruising or bleeding, as this could mean that too few blood cells of a particular type are being produced.
• if you suddenly feel unwell (even with a normal temperature).
• any yellowing of the whites of the eyes or skin (jaundice).

Talk to your doctor if you have any of the following side effects which may also happen with this medicine:

Very common (may affect more than 1 in 10 people)

• a drop in the number of your blood cells and platelets.
• jaundice (skin and the whites of the eyes turn yellow) and severe liver damage (symptoms include fatigue and nausea followed by pruritus, dark urine and may include rash or fever) - with long term use or high doses of Tioguanine – this may also show up in your blood tests.

Common (may affect up to 1 in 10 people)

• liver damage which can cause jaundice (skin and the whites of the eyes turn yellow) or an enlarged liver (a swelling below your ribcage) – with short term use of Tioguanine – this may also show up in your blood tests.
• feeling or being sick (nausea or vomiting), diarrhoea and mouth ulcers.
• Increased uric acid concentrations in the blood (hyperuricaemia), which can sometimes lead to decreased kidney function.

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

• a problem with your bowels, called necrotising colitis, which can cause severe stomach ache, being sick, diarrhoea, vomiting and fever.
• severe liver damage when used with other chemotherapy drugs, oral contraceptives and alcohol.

Not known: frequency cannot be estimated from the available data

• Sensitivity to light.
• Infections.

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.

The active substance is Tioguanine. Each Tioguanine tablet contains 40 mg of tioguanine.

The other ingredients are lactose monohydrate, starch (potato), acacia, stearic acid, magnesium stearate and purified water.

Tioguanine tablets are white to off-white tablets, round, biconvex scored and imprinting ‘T40’ on upper side, without score and debossing on lower side. Your Tioguanine tablets are in bottles of 25 tablets.

Marketing authorization holder:

Manufacturer: