Mercaptopurine: Uses & Side Effects

Mercaptopurine is a cancer medicine that interferes with the growth and spread of cancer cells in the body. It is used to treat acute lymphoblastic leukemia (ALL). Mercaptopurine is sometimes given with other cancer medications.

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:

  • liver disease;
  • kidney disease;
  • 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
  • ulcerative colitis (treated with mesalamine, sulfasalazine, or similar medicines).

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.

Side effects

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
  • low blood cell counts–fever, sore throat, weakness, pale skin, cold hands and feet, feeling light-headed or short of breath.

Common side effects may include:

  • nausea, vomiting, loss of appetite;
  • diarrhea;
  • rash; or
  • general ill feeling.

Keyword: mercaptopurine.

* The Content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition.