Purinethol (Mercaptopurine)

Follow all directions on your prescription label. Your doctor may occasionally change your dose to make sure you get the best results. Do not take this medicine in larger or smaller amounts or for longer than recommended.

Shake the oral suspension (liquid) well just before you measure a dose. Measure liquid medicine with the dosing syringe provided, or with a special dose-measuring spoon or medicine cup. If you do not have a dose-measuring device, ask your pharmacist for one.

PURINETHOL can lower blood cells that help your body fight infections and help your blood to clot. Your blood will need to be tested often. Your kidney and liver function may also need to be checked. Your cancer treatments may be delayed based on the results of these tests.

Store at room temperature away from moisture and heat.

Seek emergency medical attention or call the Poison Help line.

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.

Get emergency medical help if you have signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Stop using PURINETHOL 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:

• signs of infection (fever, swollen gums, painful mouth sores, pain when swallowing, skin sores, cold or flu symptoms, cough, trouble breathing);
• unusual bleeding (nose, mouth, vagina, or rectum), purple or red pinpoint spots under your skin;
• severe nausea, vomiting, or diarrhea;
• pain or burning with urination; or
• bloody or tarry stools, coughing up blood or vomit that looks like coffee grounds.

Common side effects may include:

• nausea, vomiting, loss of appetite;
• diarrhea; or
• skin rash.

Some people using PURINETHOL have developed a rare fast-growing type of lymphoma (cancer). This condition affects the liver, spleen, and bone marrow, and it can be fatal.

Call your doctor at once if you have symptoms of lymphoma, such as: fever, night sweats, weight loss, tiredness, feeling full after eating only a small amount, pain in your upper stomach, easy bruising or bleeding, dark urine, or jaundice (yellowing of the skin or eyes).

You should not use PURINETHOL if you are allergic to it, or if you have ever used PURINETHOL or thioguanine (Tabloid) and they were not effective in treating your condition.

Some people using PURINETHOL 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 PURINETHOL 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 PURINETHOL is safe for you, tell your doctor if you have:

• liver disease;
• kidney disease;
• any type of viral, bacterial, or fungal infection; or
• ulcerative colitis (treated with mesalamine, sulfasalazine, or similar medicines).

Do not use PURINETHOL 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 PURINETHOL passes into breast milk or if it could harm a nursing baby. You should not breast-feed while taking PURINETHOL.

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 (urine, feces, vomit). Caregivers should wear rubber gloves while cleaning up a patient's 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.

Do not receive a "live" vaccine while using PURINETHOL, and avoid coming into contact with anyone who has recently received a live vaccine. There is a chance that the virus could be passed on to you. Live vaccines include measles, mumps, rubella (MMR), polio, rotavirus, typhoid, yellow fever, varicella (chickenpox), zoster (shingles), and nasal flu (influenza) vaccine.

Tell your doctor about all medicines you use, and those you start or stop using during your treatment with PURINETHOL, especially:

• sulfamethoxazole and trimethoprim (Bactrim, Cotrim, Septra, SMX-TMP or SMZ-TMP);
• warfarin (Coumadin, Jantoven); or
• drugs that weaken the immune system such as cancer medicine, steroids, and medicines to prevent organ transplant rejection.

This list is not complete. Other drugs may interact with PURINETHOL, including prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible interactions are listed in this medication guide.