Medically reviewed on November 15, 2017.
What is mercaptopurine?
Mercaptopurine is a cancer medicine that interferes with the growth and spread of cancer cells in the body.
Mercaptopurine is used to treat acute lymphoblastic leukemia (ALL). Mercaptopurine is sometimes given with other cancer medications.
Mercaptopurine may also be used for purposes not listed in this medication guide.
Some people using mercaptopurine have developed a rare fast-growing type of lymphoma (cancer). This condition affects the liver, spleen, and bone marrow, and it can be fatal.
Call your doctor at once if you have symptoms of lymphoma, such as: fever, night sweats, weight loss, tiredness, feeling full after eating only a small amount, pain in your upper stomach, easy bruising or bleeding, dark urine, or jaundice (yellowing of the skin or eyes).
Before taking this medicine
You should not use mercaptopurine if you are allergic to it, or if you have ever used mercaptopurine or thioguanine (Tabloid) and they were not effective in treating your condition.
Some people using mercaptopurine have developed a rare fast-growing type of lymphoma (cancer). This condition affects the liver, spleen, and bone marrow, and it can be fatal. This has occurred mainly in teenagers and young adults using mercaptopurine or similar medicines to treat Crohn's disease or ulcerative colitis.
However, people with autoimmune disorders (including rheumatoid arthritis, Crohn's disease, ankylosing spondylitis, and psoriasis) may have a higher risk of lymphoma. Talk to your doctor about your individual risk.
Using mercaptopurine may also increase your risk of developing other types of cancer, such as skin cancer or uterine cancer. Ask your doctor about your specific risk.
To make sure mercaptopurine is safe for you, tell your doctor if you have:
an inherited condition in which your body cannot produce enough of the enzyme thiopurine methyltransferase (TPMT);
any type of viral, bacterial, or fungal infection; or
Do not use mercaptopurine if you are pregnant. It could harm the unborn baby. Use effective birth control, and tell your doctor if you become pregnant during treatment.
It is not known whether mercaptopurine passes into breast milk or if it could harm a nursing baby. You should not breast-feed while taking mercaptopurine.
How should I take mercaptopurine?
Follow all directions on your prescription label. Your doctor may occasionally change your dose to make sure you get the best results. Do not take this medicine in larger or smaller amounts or for longer than recommended.
Shake the oral suspension (liquid) well just before you measure a dose. Measure liquid medicine with the dosing syringe provided, or with a special dose-measuring spoon or medicine cup. If you do not have a dose-measuring device, ask your pharmacist for one.
Use care when handling mercaptopurine oral suspension. The liquid can be dangerous if it gets in your eyes or on your skin. If this occurs, wash your skin with soap and water or rinse your eyes with water. Seek medical attention if you have redness, itching, or swelling even after rinsing off the medicine. Ask your doctor or pharmacist how to safely clean up an accidental spill.
Mercaptopurine can lower blood cells that help your body fight infections and help your blood to clot. Your blood will need to be tested often. Your liver function may also need to be checked. Your cancer treatments may be delayed based on the results of these tests.
Store at room temperature away from moisture and heat.
What happens if I miss a dose?
Call your doctor for instructions if you miss a dose of mercaptopurine.
What happens if I overdose?
Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.
What should I avoid while taking mercaptopurine?
Avoid exposure to sunlight or tanning beds. Mercaptopurine can make you sunburn more easily. Wear protective clothing and use sunscreen (SPF 30 or higher) when you are outdoors.
Avoid being near people who are sick or have infections. Tell your doctor at once if you develop signs of infection.
This medicine can pass into body fluids (urine, feces, vomit). Caregivers should wear rubber gloves while cleaning up a patient's body fluids, handling contaminated trash or laundry or changing diapers. Wash hands before and after removing gloves. Wash soiled clothing and linens separately from other laundry.
Do not receive a "live" vaccine while using mercaptopurine, and avoid coming into contact with anyone who has recently received a live vaccine. There is a chance that the virus could be passed on to you. Live vaccines include measles, mumps, rubella (MMR), polio, rotavirus, typhoid, yellow fever, varicella (chickenpox), zoster (shingles), and nasal flu (influenza) vaccine.
Mercaptopurine side effects
Get emergency medical help if you have signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.
Stop using mercaptopurine and call your doctor right away if you have any of these symptoms of lymphoma:
fever, night sweats, weight loss, tiredness;
feeling full after eating only a small amount;
pain in your upper stomach that may spread to your shoulder;
easy bruising or bleeding, pale skin, feeling light-headed or short of breath, rapid heart rate; or
nausea, upper stomach pain, itching, loss of appetite, dark urine, clay-colored stools, jaundice (yellowing of the skin or eyes).
Also call your doctor at once if you have:
skin sores with redness, swelling, or drainage;
unusual bleeding (nose, mouth, vagina, or rectum), purple or red pinpoint spots under your skin;
liver problems--loss of appetite, upper stomach pain, swelling in your midsection, dark urine, clay-colored stools, jaundice (yellowing of the skin or eyes); or
Common side effects may include:
nausea, vomiting, loss of appetite;
general ill feeling.
This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.
See also: Side effects (in more detail)
What other drugs will affect mercaptopurine?
Tell your doctor about all medicines you use, and those you start or stop using during your treatment with mercaptopurine, especially:
This list is not complete. Other drugs may interact with mercaptopurine, including prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible interactions are listed in this medication guide.
Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.
Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.
Copyright 1996-2018 Cerner Multum, Inc. Version: 10.01.
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