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Active substance(s): MERCAPTOPURINE

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50 mg tablets /
50 mg tablets
This medicine can be known by either of the above names but
will be referred to as Puri-Nethol through the remainder of this
Read all of this leaflet carefully before you start taking
this medicine because it contains important information
for you.

Keep this leaflet. You may need to read it again.

If you have any further questions about your illness or
your medicine, 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
symptoms are the same as yours.

If you get any side effects talk to your doctor, nurse or
pharmacist. This includes any possible side effects not
listed in the leaflet. See section 4.

What is in this leaflet:
What Puri-Nethol is and what it is used for
What you need to know before you take Puri-Nethol
How to take Puri-Nethol
Possible side effects
How to store Puri-Nethol
Contents of the pack and other information

Puri-Nethol tablets contain a medicine called mercaptopurine.
This belongs to a group of medicines called cytotoxics (also
called chemotherapy). Puri-Nethol is used to treat leukaemia
(cancer of the blood). It works by reducing the number of new
blood cells your body makes.
Puri-Nethol is used for:

Acute myelogenous leukaemia (also called acute
myeloid leukaemia or AML) - a fast-growing disease
that increases the number of white blood cells produced
by the bone marrow. This can cause infections and

Acute lymphoblastic leukaemia (also called acute
lymphocytic leukaemia or ALL) - a fast-growing
disease which increases the number of immature white
blood cells. These immature white blood cells are unable
to grow and work properly. They therefore cannot fight
infections and may cause bleeding.

Chronic granulocytic leukaemia (also called chronic
myeloid leukaemia) - a disease that increases the
number of white blood cells. This can cause infections
and bleeding.
Ask your doctor if you would like more explanation about
these diseases.

Do not take Puri-Nethol:

if you are allergic (hypersensitive) to mercaptopurine or
any of the other ingredients of Puri-Nethol tablets (listed
in section 6)
Do not take if the above applies to you. If you are not sure,
talk to your doctor or pharmacist before taking Puri-Nethol.

Warnings and precautions
Talk to your doctor or pharmacist before taking Puri-Nethol if:

you have a liver problem; your doctor will monitor your
liver function

you have a condition where your body produces too little
of something called TPMT or ‘thiopurine

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

Other medicines and Puri-Nethol
Tell your doctor or pharmacist if you are taking, have recently
taken or might take any other medicines, including medicines
obtained without a prescription. This includes herbal
In particular, tell your doctor or pharmacist if you are taking
any of the following:

methotrexate (used mainly to treat cancers)

other cytotoxic drugs (chemotherapy) - when used with
Puri-Nethol there is a greater chance of side effects,
such as breathing problems

allopurinol, oxipurinol and thiopurinol (used mainly to
treat gout) - when used with Puri-Nethol, only 25 % of
the normal dose of Puri-Nethol should be taken

anticoagulants such as warfarin (used to thin the blood
and prevent blood clots)

olsalazine or mesalazine (used for a bowel problem
called ulcerative colitis)

sulfasalazine (used for rheumatoid arthritis or ulcerative
colitis) ribavirin (used to treat viral infections)

Having vaccines while you are taking Puri-Nethol
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 Puri-Nethol.
Pregnancy, breast-feeding and fertility
Do not take Puri-Nethol if you are planning to have a baby.
This applies to both men and women. Puri-Nethol may harm
your sperm or eggs. Reliable contraceptive precautions must
be taken to avoid pregnancy whilst you or your partner are
taking these tablets. Ask your doctor for advice.
Treatment with Puri-Nethol is not recommended during
pregnancy, particularly in the first three months, because it
may cause permanent damage to a foetus. If you think you
could be pregnant, or if you are planning to become pregnant,
check with your doctor before taking Puri-Nethol. Your doctor
will consider the risks and benefits to you and your baby of
taking Puri-Nethol.
Do not breast-feed while taking Puri-Nethol. Ask your doctor
or midwife for advice.

Puri-Nethol tablets contain lactose
If you have been told by your doctor that you have an
intolerance to some sugars, contact your doctor before you
take Puri-Nethol tablets.



Puri-Nethol should only be given to you by a specialist doctor
who is experienced in treating blood problems.
Always take Puri-Nethol exactly as your doctor has told you. It
is important to take your medicine at the right times. The label
on your pack will tell you how many tablets to take and how
often to take them. If the label doesn’t say or if you are not
sure, ask your doctor, nurse or pharmacist.

You should take Puri-Nethol tablets at least 1 hour
before or 3 hours after food or milk.

Swallow your tablets whole with a glass of water.

When you take Puri-Nethol your doctor will take regular
blood tests. This is to check the number and type of cells
in your blood and to ensure your liver is working

Your doctor may also ask for other blood and urine tests
to monitor your uric acid levels. Uric acid is a natural
body chemical, levels of which can rise while taking PuriNethol.

Your doctor may sometimes change your dose of PuriNethol as a result of these tests.
The dose of Puri-Nethol you are given will be worked out by
your doctor based on:

your body size (surface area)

the results of your blood tests

The usual starting dose for adults and children is 2.5 mg
per kilogram of your body weight each day.

Elderly patients will have their kidney and liver function
tested and if necessary the dose may need to be
Overweight children may have to take doses at the
higher end of the recommended dose range. Their
doctor will closely assess how they respond to
Children with acute lymphoblastic leukaemia may be
asked by their doctor to take Puri-Nethol tablets in the
evening as this may lower the risk of the leukaemia
getting worse again in the future.
Patients with kidney or liver problems may need to have
their dose reduced.
If you have a condition where your body produces too
little of something called TPMT or ‘thiopurine
methyltransferase’, your dose may be reduced.

The score line is not intended for breaking the tablet.
If you take more Puri-Nethol than you should
If you take more Puri-Nethol than you should, tell your doctor
immediately or go to a hospital straight away. Take the
medicine pack with you.

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


lymphoma in patients with Inflammatory Bowel Disease
(an unlicensed use of Puri-Nethol) when Puri-Nethol is
taken with other drugs called anti-TNF agents.

ulcers in the intestines

in men: low sperm count

allergic reaction (hypersensitivity) with:
- facial swelling
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

Reporting of side effects
If you get any side effects, talk to your doctor, nurse or
pharmacist. This includes any possible side effects not listed
in this leaflet. You can also report side effects directly via the
Yellow Card Scheme at:
By reporting side effects you can help provide more
information on the safety of this medicine.

If you forget to take Puri-Nethol
Tell your doctor. Do not take a double dose to make up for
a forgotten dose.



Keep out of the sight and reach of children.

Do not store above 25°C.

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

Keep the bottle tightly closed.

Protect from moisture.

Protect from light.

Do not use Puri-Nethol after the expiry date which is
stated on the pack after ‘EXP’.

If your doctor tells you to stop taking the tablets, it is
important to return any which are left over to your
pharmacist, who will destroy them according to disposal
of dangerous substance guidelines. Only keep the
tablets if your doctor tells you to.

If the tablets show any signs of deterioration seek the
advice of your pharmacist.




Like all medicines, Puri-Nethol can cause side effects,
although not everybody gets them.
If you get any of the following, talk to your specialist
doctor or go to hospital straight away:

allergic reaction, the signs may include:
- skin rashes
- high temperature
- joint pain
- swollen face

any signs of fever or infection (sore throat, sore mouth or
urinary problems). Treatment with mercaptopurine
causes a lowering of the white blood cell count. White
blood cells fight infection, and when there are too few
white blood cells, infections can occur.

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

any yellowing of the whites of the eyes or skin (jaundice)

if you have diarrhoea

if you feel sick (nausea) or you are sick (vomiting).
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 white blood cells and platelets
Common (may affect up to 1 in 10 people)

feeling or being sick (nausea or vomiting)

inflammation of the pancreas, which can give you
abdominal pain or make you sick, for patients with
Inflammatory Bowel Disease (an unlicensed use of PuriNethol)

liver problems - this may show up in your blood tests

yellow discolouration of your skin and/or pain under your
ribs and around the area of your stomach (biliary stasis)
Uncommon (may affect up to 1 in 100 people)

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

mouth ulcers

inflammation of the pancreas which can give you
abdominal pain or make you sick

hair loss

severe damage to liver cells (hepatic necrosis)

allergic reaction (hypersensitivity) with:
- skin rash
- persistent fever

What Puri-Nethol contains
The active ingredient is mercaptopurine.
Each tablet contains 50 mg of mercaptopurine.
The other ingredients are lactose, starch, modified starch,
magnesium stearate and stearic acid.

What Puri-Nethol looks like and contents of the pack
Puri-Nethol tablets are pale yellow, circular, biconvex tablets,
scored on one side and engraved ‘GX’ above the score and
‘EX2’ below the score and plain on the reverse.
Your Puri-Nethol tablets are in bottles of 25 tablets.
This product is manufactured by EXCELLA GmbH,
Nürnberger Strasse 12, Feucht, Germany. Procured from
within the EU and repackaged by Mediwin Limited. Product
Licence Holder: Mediport Limited. 13 Martello Enterprise
Centre, Courtwick Lane, Littlehampton, West Sussex, BN17
7PA, United Kingdom.

PL: 18980/0862

PURI-NETHOL is a registered trademark of Aspen Global
Date of leaflet preparation: 15/06/2015
To request a copy of this leaflet in Braille. Large print or audio
Please call 0800 198 5000 (UK only).

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Source: Medicines and Healthcare Products Regulatory Agency

Disclaimer: Every effort has been made to ensure that the information provided here is accurate, up-to-date and complete, but no guarantee is made to that effect. Drug information contained herein may be time sensitive. This information has been compiled for use by healthcare practitioners and consumers in the United States. The absence of a warning for a given drug or combination thereof in no way should be construed to indicate that the drug or combination is safe, effective or appropriate for any given patient. If you have questions about the substances you are taking, check with your doctor, nurse or pharmacist.