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mercaptopurine

Pronunciation

Generic Name: mercaptopurine (mer KAP toe PURE een)
Brand Name: Purinethol

What is mercaptopurine?

Mercaptopurine is a cancer medication that interferes with the growth and spread of cancer cells in the body.

Mercaptopurine is used to treat certain types of leukemia. Mercaptopurine is sometimes given with other cancer medications.

Mercaptopurine may also be used for purposes not listed in this medication guide.

What is the most important information I should know about mercaptopurine?

Do not use mercaptopurine if you are pregnant. It could harm the unborn baby.

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.

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Call your doctor at once if you have any of the following symptoms: fever, night sweats, itching, loss of appetite, weight loss, tiredness, feeling full after eating only a small amount, pain in your upper stomach that may spread to your shoulder, nausea, easy bruising or bleeding, pale skin, feeling light-headed or short of breath, rapid heart rate, dark urine, clay-colored stools, or jaundice (yellowing of the skin or eyes).

Mercaptopurine can lower blood cells that help your body fight infections. Your blood may need to be tested often. Avoid being near people who are sick or have infections. Avoid activities that may increase your risk of bleeding injury. Tell your doctor at once if you develop signs of infection.

What should I discuss with my healthcare provider before taking mercaptopurine?

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.

To make sure you can safely take mercaptopurine, tell your doctor if you have any of these other conditions:

  • liver disease;

  • kidney disease; or

  • any type of viral, bacterial, or fungal infection.

FDA pregnancy category D. 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?

Take exactly as prescribed by your doctor. Do not take in larger or smaller amounts or for longer than recommended. Follow the directions on your prescription label.

Your doctor may occasionally change your dose to make sure you get the best results.

Mercaptopurine can lower blood cells that help your body fight infections. Your blood cells, kidney function, and liver function may need to be tested often. Your cancer treatments may be delayed based on the results of these tests. Do not miss any follow up visits to your doctor for blood or urine tests.

Store at room temperature away from moisture and heat.

What happens if I miss a dose?

Take the missed dose as soon as you remember. Skip the missed dose if it is almost time for your next scheduled dose. Do not take extra medicine to make up the missed dose.

What happens if I overdose?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

Overdose symptoms may include some of the serious side effects listed in this medication guide.

What should I avoid while taking mercaptopurine?

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 (including urine, feces, vomit, semen, vaginal fluid). For at least 48 hours after you receive a dose, avoid allowing your body fluids to come into contact with your hands or other surfaces. Patients and caregivers should wear rubber gloves while cleaning up 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.

Body fluids should not be handled by a woman who is pregnant or who may become pregnant. Use condoms during sexual activity to avoid exposure to body fluids.

Do not receive a "live" vaccine while using mercaptopurine. The vaccine may not work as well during this time, and may not fully protect you from disease. Live vaccines include measles, mumps, rubella (MMR), oral polio, rotavirus, typhoid, varicella (chickenpox), H1N1 influenza, and nasal flu vaccine.

Mercaptopurine side effects

Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficulty 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).

Stop using mercaptopurine and call your doctor at once if you have any of these other serious side effects:

  • signs of infection (fever, chills, sore throat, body aches, weakness, muscle pain, flu symptoms);

  • severe nausea, vomiting, or diarrhea;

  • bloody or tarry stools, coughing up blood or vomit that looks like coffee grounds;

  • pain or burning with urination; or

  • white patches or sores inside your mouth or on your lips.

Less serious side effects may include:

  • vomiting, mild diarrhea;

  • hair loss;

  • mild itching or skin rash; or

  • darkened skin color.

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)

Mercaptopurine Dosing Information

Usual Adult Dose for Intestinal Arterial Insufficiency:

Initial Dosage:
Oral: 2.5 mg/kg of body weight per day (100 to 200 mg in the average adult). This dose may be continued daily for several weeks or more in some patients. If, after 4 weeks at this dosage, there is no clinical improvement and no definite evidence of leukocyte or platelet depression, the dosage may be increased up to 5 mg/kg daily. A dosage of 2.5 mg/kg per day may result in a rapid fall in leukocyte count within 1 to 2 weeks in some adults with acute lymphatic leukemia and high total leukocyte counts.

The total daily dosage may be given at one time. It is calculated to the nearest multiple of 25 mg.

Maintenance Therapy: Once a complete hematologic remission is obtained, maintenance therapy is considered essential. A usual daily maintenance dose of mercaptopurine is 1.5 to 2.5 mg/kg per day as a single dose. Mercaptopurine should rarely be relied upon as a single agent for the maintenance of remissions induced in acute leukemia.

Usual Adult Dose for Acute Lymphoblastic Leukemia:

Initial Dosage:
Oral: 2.5 mg/kg of body weight per day (100 to 200 mg in the average adult). This dose may be continued daily for several weeks or more in some patients. If, after 4 weeks at this dosage, there is no clinical improvement and no definite evidence of leukocyte or platelet depression, the dosage may be increased up to 5 mg/kg daily. A dosage of 2.5 mg/kg per day may result in a rapid fall in leukocyte count within 1 to 2 weeks in some adults with acute lymphatic leukemia and high total leukocyte counts.

The total daily dosage may be given at one time. It is calculated to the nearest multiple of 25 mg.

Maintenance Therapy: Once a complete hematologic remission is obtained, maintenance therapy is considered essential. A usual daily maintenance dose of mercaptopurine is 1.5 to 2.5 mg/kg per day as a single dose. Mercaptopurine should rarely be relied upon as a single agent for the maintenance of remissions induced in acute leukemia.

Usual Adult Dose for Crohn's Disease -- Acute:

Oral: 1.0 to 1.5 mg/kg of body weight per day

Usual Adult Dose for Crohn's Disease -- Maintenance:

Oral: 1.0 to 1.5 mg/kg of body weight per day

Usual Adult Dose for Ulcerative Colitis -- Maintenance:

Oral: 1.0 to 1.5 mg/kg of body weight per day

Usual Adult Dose for Inflammatory Bowel Disease:

Oral: 1.0 to 1.5 mg/kg of body weight per day

Usual Pediatric Dose for Intestinal Arterial Insufficiency:

Initial Dosage:
Oral: 2.5 mg/kg of body weight per day (50 mg in an average 5-year-old child). Pediatric patients with acute leukemia have tolerated this dose without difficulty in most cases; it may be continued daily for several weeks or more in some patients. If, after 4 weeks at this dosage, there is no clinical improvement and no definite evidence of leukocyte or platelet depression, the dosage may be increased up to 5 mg/kg daily. A dosage of 2.5 mg/kg per day may result in a rapid fall in leukocyte count within 1 to 2 weeks in some adults with acute lymphatic leukemia and high total leukocyte counts.

The total daily dosage may be given at one time. It is calculated to the nearest multiple of 25 mg.

Maintenance Therapy: Once a complete hematologic remission is obtained, maintenance therapy is considered essential. A usual daily maintenance dose of mercaptopurine is 1.5 to 2.5 mg/kg per day as a single dose. It is to be emphasized that in pediatric patients with acute lymphatic leukemia in remission, superior results have been obtained when mercaptopurine has been combined with other agents (most frequently with methotrexate) for remission maintenance. Mercaptopurine should rarely be relied upon as a single agent for the maintenance of remissions induced in acute leukemia.

Usual Pediatric Dose for Acute Lymphoblastic Leukemia:

Initial Dosage:
Oral: 2.5 mg/kg of body weight per day (50 mg in an average 5-year-old child). Pediatric patients with acute leukemia have tolerated this dose without difficulty in most cases; it may be continued daily for several weeks or more in some patients. If, after 4 weeks at this dosage, there is no clinical improvement and no definite evidence of leukocyte or platelet depression, the dosage may be increased up to 5 mg/kg daily. A dosage of 2.5 mg/kg per day may result in a rapid fall in leukocyte count within 1 to 2 weeks in some adults with acute lymphatic leukemia and high total leukocyte counts.

The total daily dosage may be given at one time. It is calculated to the nearest multiple of 25 mg.

Maintenance Therapy: Once a complete hematologic remission is obtained, maintenance therapy is considered essential. A usual daily maintenance dose of mercaptopurine is 1.5 to 2.5 mg/kg per day as a single dose. It is to be emphasized that in pediatric patients with acute lymphatic leukemia in remission, superior results have been obtained when mercaptopurine has been combined with other agents (most frequently with methotrexate) for remission maintenance. Mercaptopurine should rarely be relied upon as a single agent for the maintenance of remissions induced in acute leukemia.

What other drugs will affect mercaptopurine?

Tell your doctor about all other cancer treatments you are receiving. Also tell your doctor about all other medicines you use, especially:

  • acetaminophen;

  • allopurinol;

  • auranofin;

  • azathioprine;

  • cyclosporine;

  • methotrexate;

  • olsalazine, mesalamine, or sulfasalazine;

  • sulfamethoxazole and trimethoprim;

  • thioguanine;

  • birth control pills or hormone replacement therapy;

  • a blood thinner such as warfarin;

  • an NSAID (non-steroidal anti-inflammatory drug) such as ibuprofen, naproxen, celecoxib, diclofenac, indomethacin, meloxicam, and others; or

  • an ACE inhibitor such as benazepril, enalapril, lisinopril, quinapril, ramipril, and others;

  • an antibiotic such as dapsone, erythromycin, or rifampin;

  • tuberculosis medications;

  • cholesterol medications such as niacin, atorvastatin, simvastatin, lovastatin, pravastatin, and others;

  • HIV/AIDS medications such as abacavir/lamivudine/zidovudine, lamivudine, nevirapine, tenofovir, or zidovudine;

  • antifungal medication such as fluconazole, itraconazole, or ketoconazole; or

  • seizure medications such as carbamazepine, phenytoin, felbamate, valproic acid.

This list is not complete and other drugs may interact with mercaptopurine. Tell your doctor about all medications you use. This includes prescription, over-the-counter, vitamin, and herbal products. Do not start a new medication without telling your doctor.

Where can I get more information?

  • Your doctor or pharmacist can provide more information about mercaptopurine.
  • 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.
  • Disclaimer: Every effort has been made to ensure that the information provided by Cerner Multum, Inc. ('Multum') is accurate, up-to-date, and complete, but no guarantee is made to that effect. Drug information contained herein may be time sensitive. Multum information has been compiled for use by healthcare practitioners and consumers in the United States and therefore Multum does not warrant that uses outside of the United States are appropriate, unless specifically indicated otherwise. Multum's drug information does not endorse drugs, diagnose patients or recommend therapy. Multum's drug information is an informational resource designed to assist licensed healthcare practitioners in caring for their patients and/or to serve consumers viewing this service as a supplement to, and not a substitute for, the expertise, skill, knowledge and judgment of healthcare practitioners. The absence of a warning for a given drug or drug combination in no way should be construed to indicate that the drug or drug combination is safe, effective or appropriate for any given patient. Multum does not assume any responsibility for any aspect of healthcare administered with the aid of information Multum provides. The information contained herein is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. If you have questions about the drugs you are taking, check with your doctor, nurse or pharmacist.

Copyright 1996-2012 Cerner Multum, Inc. Version: 9.02. Revision Date: 2013-07-08, 4:04:06 PM.

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