Find & Manage Your Patient Assistance Programs
Estimated patient savings $600,000,000.00

Important Note

The following information is intended to supplement, not substitute for, the expertise and judgment of your physician, pharmacist or other healthcare professional. It should not be construed to indicate that use of the drug is safe, appropriate, or effective for you. Consult your healthcare professional before using this drug.





Mercaptopurine is used to treat leukemia. It is also used for pediatric non-Hodgkin's lymphoma, polycythemia vera, and psoriatic arthritis.



This medication may also be used for inflammatory bowel disease.

How To Use

This is a potent medication. Take it exactly as prescribed. Unless your doctor instructs you otherwise, drink plenty of fluids to avoid dehydration. Contact your doctor if you vomit shortly after taking your dose.

Side Effects

Diarrhea, nausea, vomiting, loss of appetite, stomach/abdominal pain, weakness, skin rash, darkening of the skin, or hair loss may occur. If any of these effects persist or worsen, notify your doctor or pharmacist promptly. Tell your doctor immediately if any of these serious side effects occur: mouth sores, fever, sore throat, easy bruising or bleeding, pinpoint red spots on the skin, yellowing of eyes or skin, dark urine, painful or difficult urination. Tell your doctor immediately if any of these unlikely but serious side effects occur: black or tarry stools, blood in urine or stool. An allergic reaction to this drug is unlikely, but seek immediate medical attention if it occurs. Symptoms of an allergic reaction include: rash, itching, swelling, dizziness, trouble breathing. If you notice other effects not listed above, contact your doctor or pharmacist.


Tell your doctor your medical history, especially of: kidney disease, liver disease, any infections, previous anti-cancer treatment, blood disorders, recent exposure to chickenpox, any allergies you may have. This medication can lower your body's ability to fight an infection. Notify your doctor if you develop any signs of infection such as fever, sore throat, rash or chills. Avoid touching your eyes or inside your nose without first washing your hands. Use caution with sharp objects like safety razors or nail cutters and avoid activities such as contact sports in order to lower the chance of getting cut, bruised or injured. Do not have immunizations/vaccinations without consent of your doctor and avoid contact with people who have recently received oral polio vaccine. Drinking alcohol may increase the possibility of developing stomach (GI tract) irritation or liver damage. Contraceptive (birth control) measures are recommended for use in men and women while taking this medication. This medication is not recommended for use during pregnancy. Consult your doctor. It is not known if this drug passes into breast milk. Because this is a powerful drug and may affect a nursing infant, consult your doctor before breast-feeding.

Drug Interactions

Tell your doctor of all prescription and nonprescription drugs you may use, especially of: allopurinol, warfarin, certain drugs to treat ulcerative colitis (e.g., olsalazine, mesalazine, sulfasalazine). Do not start or stop any medicine without doctor or pharmacist approval.


If overdose is suspected, contact your local poison control center or emergency room immediately. Symptoms of overdose may include severe nausea, vomiting, diarrhea, fever, and weakness.


Regular doctor visits are important. Keep all medical appointments. Blood tests will be done to monitor your progress.

Missed Dose

Take the dose as soon as remembered but if it is almost time to take your next dose, skip the missed dose and resume your regular dosing schedule. Do not double dose to catch up.


Store at room temperature away from sunlight and moisture.

Medical Alert

Your condition can cause complications in a medical emergency. For enrollment information call MedicAlert at 1-800-854-1166 (USA), or 1-800-668-1507 (Canada).