Mercaptopurine is used alone or with other chemotherapy drugs to treat acute lymphocytic leukemia (ALL; also called acute lymphoblastic leukemia and acute lymphatic leukemia; a type of cancer that begins in the white blood cells). Mercaptopurine is in a class of medications called purine antagonists. It works by stopping the growth of cancer cells.
Mercaptopurine comes as a tablet and a suspension (liquid) to take by mouth. It is usually taken once a day. Take mercaptopurine at around the same time every day. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take mercaptopurine exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.
If you are taking the suspension, shake the bottle very well for 30 seconds before each use to mix the medication evenly. It is important to use an oral syringe (measuring device) to accurately measure and take your dose of mercaptopurine. If you do not find an oral syringe with your medication, ask your pharmacist to give you one. After you use the oral syringe to take your medication, remove the plunger from the rest of the measuring device, wash both parts with warm soapy water, and rinse under running tap water. Allow the parts to air dry before putting back together for the next use.
Continue to take mercaptopurine even if you feel well. Do not stop taking mercaptopurine without talking to your doctor
Mercaptopurine is also sometimes used to treat certain other types of cancer, Crohn's disease (a condition in which the body attacks the lining of the digestive tract causing pain, diarrhea, weight loss, and fever), and ulcerative colitis (condition in which sores develop in the intestines causing pain and diarrhea). Talk to your doctor about the possible risks of using this medication for your condition.
This medication may be prescribed for other uses; ask your doctor or pharmacist for more information.
Before taking mercaptopurine,
Unless your doctor tells you otherwise, continue your normal diet.
Take the missed dose as soon as you remember it. However, if it is almost time for the next dose, skip the missed dose and continue your regular dosing schedule. Do not take a double dose to make up for a missed one.
Mercaptopurine may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:
Some side effects can be serious. If you experience any of these symptoms, call your doctor immediately:
Taking mercaptopurine may increase the risk that you will develop a new cancer. Some people who took mercaptopurine to treat Crohn's disease or ulcerative colitis developed hepatosplenic T cell lymphoma (HSTCL), a very serious form of cancer that often causes death within a short time. Tell your doctor if you experience any of the following symptoms: stomach pain; fever; unexplained weight loss; night sweats or easy bruising or bleeding. Talk to your doctor about the risks of taking this medication.
Mercaptopurine may cause other side effects. Call your doctor if you have any unusual problems while you are taking this medication.
If you experience a serious side effect, you or your doctor may send a report to the Food and Drug Administration's (FDA) MedWatch Adverse Event Reporting program online ( Web Site ) or by phone (1-800-332-1088).
Keep this medication in the container it came in, tightly closed, and out of reach of children. Store it at room temperature and away from excess heat and moisture (not in the bathroom). Mercaptopurine suspension can be kept at room temperature for up to 6 weeks after the bottle is opened for the first time. Then, dispose of any suspension that is left over after 6 weeks.
Unneeded medications should be disposed of in special ways to ensure that pets, children, and other people cannot consume them. However, you should not flush this medication down the toilet. Instead, the best way to dispose of your medication is through a medicine take-back program. Talk to your pharmacist or contact your local garbage/recycling department to learn about take-back programs in your community. See the FDA's Safe Disposal of Medicines website ( Web Site) for more information if you do not have access to a take-back program.
It is important to keep all medication out of sight and reach of children as many containers (such as weekly pill minders and those for eye drops, creams, patches, and inhalers) are not child-resistant and young children can open them easily. To protect young children from poisoning, always lock safety caps and immediately place the medication in a safe location – one that is up and away and out of their sight and reach. Web Site
In case of overdose, call the poison control helpline at 1-800-222-1222. Information is also available online at Web Site. If the victim has collapsed, had a seizure, has trouble breathing, or can't be awakened, immediately call emergency services at 911.
Symptoms of overdose may include:
Keep all appointments with your doctor and the laboratory. Your doctor will order certain lab tests to check your body's response to mercaptopurine.
Do not let anyone else take your medication. Ask your pharmacist any questions you have about refilling your prescription.
It is important for you to keep a written list of all of the prescription and nonprescription (over-the-counter) medicines you are taking, as well as any products such as vitamins, minerals, or other dietary supplements. You should bring this list with you each time you visit a doctor or if you are admitted to a hospital. It is also important information to carry with you in case of emergencies.
AHFS® Consumer Medication Information. © Copyright, The American Society of Health-System Pharmacists, Inc., 7272 Wisconsin Avenue, Bethesda, Maryland. All Rights Reserved. Duplication for commercial use must be authorized by ASHP.
Selected Revisions: August 15, 2017.