What is Purinethol (mercaptopurine), and how does it work?
Generic drug: Purinethol
Brand name: mercaptopurine
Purinethol (mercaptopurine) is used to slow the growth of cancer cells. Purinethol is also used to treat certain types of leukemia.
What are the side effects of Purinethol?
Common side effects of Purinethol include:
Temporary hair loss may also occur. Normal hair growth should return after treatment with Purinethol has ended. Tell your doctor if you have unlikely but serious side effects of Purinethol including:
- easy bruising or bleeding,
- joint pain or swelling,
- tongue or mouth sores or pain,
- unusual tiredness, or
- symptoms of liver disease (such as persistent nausea or vomiting, stomach or abdominal pain, dark urine, yellowing eyes or skin).
Purinethol (mercaptopurine) is a potent drug. It should not be used unless a diagnosis of acute lymphatic leukemia has been adequately established and the responsible physician is experienced with the risks of Purinethol and knowledgeable in assessing response to chemotherapy.
What is the dosage for Purinethol?
- The recommended starting dosage of Purinethol is 1.5 mg/kg to 2.5 mg/kg orally once daily as part of combination chemotherapy maintenance regimen. A recommended dosage for patients less than 17 kg is not achievable, because the only available strength is 50 mg. Take Purinethol either consistently with or without food.
- After initiating Purinethol, monitor complete blood count (CBC) and adjust the dose to maintain absolute neutrophil count (ANC) at a desirable level and for excessive myelosuppression. Evaluate the bone marrow in patients with prolonged myelosuppression or repeated episodes of myelosuppression to assess leukemia status and marrow cellularity.
- Evaluate thiopurine S-methyltransferase (TPMT) and nucleotide diphosphatase (NUDT15) status in patients with severe myelosuppression or repeated episodes or myelosuppression [see Dosage Modifications in Patients with TPMT and NUDT15 Deficiency below].
- Do not administer to patients who are unable to swallow tablets.
- If a patient misses a dose, instruct the patient to continue with the next scheduled dose.
- Purinethol is a cytotoxic drug. Follow special handling and disposal procedures.
Dosage Modifications In Patients With TPMT And NUDT15 Deficiency
- Consider testing for TPMT and NUDT15 deficiency in patients who experience severe myelosuppression or repeated episodes of myelosuppression.
Homozygous Deficiency In Either TPMT Or NUDT15
- Patients with homozygous deficiency of either enzyme typically require 10% or less of the recommended dosage.
- Reduce the recommended starting dosage of Purinethol in patients who are known to have homozygous TPMT or NUDT15 deficiency.
Heterozygous Deficiency In TPMT And/Or NUDT15
- Reduce the Purinethol dose based on tolerability.
- Most patients with heterozygous TPMT or NUDT15 deficiency tolerate the recommended dosage, but some require a dose reduction based on adverse reactions.
- Patients who are heterozygous for both TPMT and NUDT15 may require more substantial dose reductions.
Dosage Modifications In Renal And Hepatic Impairment
- Use the lowest recommended starting dosage for Purinethol in patients with renal impairment (CLcr less than 50 mL/min).
- Adjust the dosage to maintain absolute neutrophil count (ANC) at a desirable level and for adverse reactions.
- Use the lowest recommended starting dosage for Purinethol in patients with hepatic impairment.
- Adjust the dosage to maintain absolute neutrophil count (ANC) at a desirable level and for adverse reactions.
Dosage Modification With Concomitant Use Of Allopurinol
- Reduce the dose of Purinethol to one-third to one-quarter of the current dosage when coadministered with allopurinol.
What drugs interact with Purinethol?
- The concomitant administration of Purinethol and warfarin may decrease the anticoagulant effectiveness of warfarin.
- Monitor the international normalized ratio (INR) in patients receiving warfarin and adjust the warfarin dosage as appropriate.
- Purinethol can cause myelosuppression. Myelosuppression may be increased when Purinethol is coadministered with other products that cause myelosuppression. Enhanced myelosuppression has been noted in some patients also receiving trimethoprim-sulfamethoxazole. Monitor the CBC and adjust the dose of Purinethol for excessive myelosuppression.
- Aminosalicylates (e.g., mesalamine, olsalazine or sulfasalazine) may inhibit the TPMT enzyme, which may increase the risk of myelosuppression when coadministered with Purinethol. When aminosalicylates and Purinethol are coadministered, use the lowest possible doses for each drug and monitor more frequently for myelosuppression.
- Purinethol can cause hepatotoxicity. Hepatotoxicity may be increased when Purinethol is coadministered with other products that cause hepatotoxicity. Monitor liver tests more frequently in patients who are receiving Purinethol with other hepatotoxic products.
Is Purinethol safe to use while pregnant or breastfeeding?
- Purinethol can cause fetal harm when administered to a pregnant woman.
- Pregnant women who receive mercaptopurine have an increased incidence of miscarriage and stillbirth.
- There are no data on the presence of mercaptopurine or its metabolites in human milk, the effects on the breastfed child, or the effects on milk production.
- Because of the potential for serious adverse reactions in the breastfed child, women should not breastfeed during treatment with Purinethol and for 1 week after the last dose.
- Attachment Theory: What It Is, Stages & the Different Attachment Styles
- Gentle Parenting: What It Is, Techniques & Discipline
- U.S. Nursing Homes Fail to Report Many Serious Falls, Bedsores: Study
- The Younger You Get Diabetes, the Higher Your Risk for Dementia Later
- FDA Grants Full Approval to Paxlovid to Treat COVID-19
- More Health News »
Purinethol (mercaptopurine) is used to slow the growth of cancer cells. Purinethol is also used to treat certain types of leukemia. Common side effects of Purinethol include nausea, vomiting, diarrhea, loss of appetite, itching or skin rash, or darkened skin color. Temporary hair loss may also occur.
Multimedia: Slideshows, Images & Quizzes
Signs of Prostate Cancer: Symptoms, PSA Test, Treatments
What is prostate cancer? Prostate cancer is the most common cancer in men. Learn the signs and symptoms of prostate cancer, along...
Understanding Cancer: Metastasis, Stages of Cancer, and More
Learn the basics about cancer including types, causes, how it spreads, symptoms and signs, stages and treatment options. Read...
Signs of Cancer in Women: Symptoms You Can't Ignore
Colon and stomach cancer symptoms can surprise women but can be treated if detected early. Learn about breast cancer signs and...
Cancer: Guide to Leukemia
Learn about the common types and stages of leukemia, who gets it, symptoms, tests, treatments, and more. People with blood cancer...
Cancer-Fighting Foods: Resveratrol, Green Tea, and More
Experts have praised certain foods for their ability to reduce cancer risks. Learn which foods and eating strategies may help...
Blood Cancer Types: Leukemia, Lymphomas, Myelomas, and More
Types of blood cancers include leukemia, lymphomas, multiple myelomas, and others discussed in this slideshow. Symptoms may...
Top 10 Cancers Quiz
Take this quiz to learn the causes of cancer. Get the facts about the causes, symptoms, and treatments for the world's most...
What do you know about leukemia? Did you know there are different types? What are the symptoms? Take the Leukemia Quiz and test...
Cancer: Visual Guide to Thyroid Cancer
Find out the symptoms of thyroid cancer, and learn how to treat it after you get a diagnosis.
Cancer: Does This Cause Cancer?
Everything gives you cancer, right? Not really. WebMD's slide show tells you about the research into cancer and cell phones,...
Cancer: How to Lower and Cut Your Risk of Cancer
About a third of all cases of cancer can be prevented. Find out how to lower your chances of getting it.
Cancer: Guide to Testicular Cancer
Testicular cancer is one of the most common cancers for men ages 15 to 35, but it's very treatable. WebMD explains when to see...
Cancer: Symptoms of Common Cancers in Men
Can men get breast cancer? Cancer symptoms men need to watch out for include skin changes, difficulty swallowing, rapid weight...
Cancer: Cancer 'Remedies' That Don't Work
You may have read about an all-natural cure for cancer. While many therapies are helpful, some aren't worth your time or money....
Cancer Guide to Eye Cancers
Find out more from WebMD about the early signs of these types of cancer and how they’re diagnosed and treated.
Related Disease Conditions
Cancer is a disease caused by an abnormal growth of cells, also called malignancy. It is a group of 100 different diseases, and is not contagious. Cancer can be treated through chemotherapy, a treatment of drugs that destroy cancer cells.
Leukemia is a type of cancer of the blood cells in which the growth and development of the blood cells are abnormal. Strictly speaking, leukemia should refer only to cancer of the white blood cells (the leukocytes) but in practice, it can apply to malignancy of any cellular element in the blood or bone marrow, as in red cell leukemia (erythroleukemia).
What Is the Life Expectancy of a Person With Leukemia?
Leukemia is a group of cancers of the blood affecting the white blood cells. White blood cells are the infection-fighting cells of the body. In adults, leukemia is most common in people older than 55 years, with the average age of diagnosis being 66 years. It is also one of the most common cancers in children and adults younger than 20 years. The survival rate is higher for younger people.
Cancer Risk Factors and Causes
Though it's difficult to say why some people develop cancer while others don't, research shows that certain risk factors increase a person's odds of developing cancer. These risk factors include growing older, family history of cancer, diet, alcohol and tobacco use, and exposure to sunlight, ionizing radiation, certain chemicals, and some viruses and bacteria.
How Does Leukemia Kill?
Leukemia is a cancer of the white blood cells of the bone marrow. Patients with leukemia have an over-production of a particular blood cell type in the body, the white blood cells (cells that fight infection, and provide immunity).
Survival Rate for Acute Lymphoblastic Leukemia
The prognosis depends on the type of leukemia, the extent of the disease, age of the patient, and the general condition of the patient. Some patients can go into complete remission. The average five-year survival rate of leukemia is 60-65%.
What Type of Cancer Makes You Very Tired?
Extreme and recurrent tiredness is one of the common symptoms of most types of cancers. Tiredness is usually considered a warning sign of cancer progressing. Tiredness related to cancers usually does not get better with adequate rest or sleep.
What Is the Breast Cancer BRCA Gene Test?
BRCA genes (BRCA 1 and 2, when normal, repair damaged DNA) are among the genetic mutations linked to breast cancer, ovarian cancer, and other cancers when mutated. Every woman with a BRCA mutation is at high risk for breast cancer, irrespective of whether she has a family history of breast cancer or not. By age 80, a woman with a BRCA mutation has about an 80% chance of developing breast cancer. BRCA1 and BRCA2 gene mutations also increase the risk of ovarian cancer, by 54% and 23%, respectively.
Which Is the Deadliest Cancer?
Lung cancer is considered to be the most deadly cancer. More people die from lung cancer each year than from breast, colorectal and prostate cancer combined.
Cancer pain is a common experience that may result from the disease, treatment, or diagnostic procedure. Check out the center below for more medical references on cancer, including multimedia (slideshows, images, and quizzes), related disease conditions, treatment and diagnosis, medications, and prevention or wellness.
Leukemia: Signs, Symptoms, And Complications
Leukemia results when the genetic material (DNA) of a single cell in the bone marrow transforms, this is called a mutation. A mutated cell does not perform body function, but it eats away the nutrition meant for the normal cells.
What Are the Stages of Chronic Lymphocytic Leukemia?
Chronic lymphocytic leukemia is a cancer of the blood and bone marrow. With this type of cancer, the marrow creates too many abnormal lymphocytes. There are five stages of chronic lymphocytic leukemia.
Treatment & Diagnosis
- Cancer: The Importance of Joining a Cancer Support Group with Selma Schimmel
- Cancer Survival and Attitude with Hamilton Jordan
- Cancer: Confronting Cancer with Humor
- Cancer Patients Need Proper Diet and Exercise
- Cancer and Green Tea
- Cancer Pain Management with Ann Reiner
- Cancer: Living Well Despite with Win Boerckel
- Cancer Treatment: Writing to Heal with Margie Davis
- Cancer: Journaling to Save Your Life
- Cancers: Children's Cancers
- Cancer: Childhood Cancer Survivors
- Cancer Research: Going the Distance
- Leukemia FAQs
- Cancer FAQs
- Cancer,Stroke & Heart Attack Risks- ReducedThrough Walking
- Cancer Care in the Elderly
- Evolution of Treatment for a Rare Type of Leukemia
- Gleevec and Chronic Myeloid Leukemia
- How Familes Cope with a Leukemia Diagnosis
- Coping with a Bad Disease - Community Counts
- A Family's Leukemia Diary - Coping
- Cancer Survivor?
- Is Multiple Myeloma the Same as Leukemia?
- Does Folic Acid Prevent Leukemia?
- Can Folic Acid Prevent Leukemia?
- 10 Cancer Symptoms That Men Ignore
- Chronic Myelogenous Leukemia (CML)
Medications & Supplements
Health Solutions From Our Sponsors
Report Problems to the Food and Drug Administration
You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.