1 What is Purinethol?

Brand: Purinethol, Purixan

Generic: Mercaptopurine

Purinethol is an antimetabolite. It is used in the treatment of acute lymphocytic leukemia (cancer of white blood cells).

It works by slowing or stopping the growth of cancer cells. It is available in the tablet and suspension form only with your doctor’s prescription.

2 What to Know Before Using

Before using Purinethol, you must know all about the risks and complications associated with it.


Inform your doctor if you are allergic to any food, preservatives, dyes, or had an allergic reaction when you used this drug before.


There are no adequate studies done which prove Mercaptopurine’s harmful effects in children. However, safety and efficacy have not been established.


This medicine does not cause any different side effects or problem than it does in younger adults. However, it should be used with caution in the elderly patient.


It is a category D drug. It is not safe to use in pregnancy. It may cause harm, abnormality in an unborn baby and can result in the loss of an unborn baby.

Breast Feeding

Mercaptopurine is not known if it can pass into breast milk or not. Do not use this medication while nursing your child.

Drug Interactions

Mercaptopurine may interact with other drugs. Your doctor should be informed of any other medicines which you are taking. He may want to change the dosage or drug. Some of them are listed below:

  • Febuxostat
  • Allopurinol
  • Olsalazine, mesalazine, sulfasalazine
  • Aspirin
  • Warfarin
  • Trimethoprim/sulfamethoxazole
  • Amiodarone
  • Erythromycin
  • Azathioprine
  • Rotavirus Vaccine, Live
  • Adenovirus Vaccine Type 4, Live
  • Adenovirus Vaccine Type 7, Live

Other Medical Conditions

Several other conditions may reduce its effectiveness.

Make sure you inform your doctor of conditions such as:

3 Proper Usage

Proper usage of Purinethol requires strict adherence to your doctor’s orders. Read the medication guide carefully. Ask your pharmacist if you have any queries.

If you are using the suspension form of this medicine, shake it for 30 seconds before using it. Measure it with measuring syringe or adaptor. Rinse the syringe with warm water after using it.

Drink plenty of water and fluids so you can pass more urine while using this drug. It will prevent any kidney problems.

If you vomit after taking this medicine, ask your doctor if you have to take the dose again or you have to follow your schedule.


It is different for different patients. Dosage mentioned below is an average dose. You must follow your doctor’s command.

Suspension or tablet forms

Adults: 1.5 to 2.5 milligrams (mg) per kilogram (kg) of body weight per day, taken as a single dose.

Missed dose

If you miss a dose, take it as soon as you remember it. If it almost a time for your next dose skips the missed dose and continue your daily schedule. Do not double the dose.


Store it at room temperature. Keep it away from children.

4 Precautions to Take

If you take Purinethol, your doctor should perform routine checkups and advise you in taking precautions. He may do a blood or urine test to check for unwanted effects.

Use an effective form of birth control methods as Mercaptopurine can harm an unborn baby.

Do not use this medicine if you have taken it in past and found it ineffective. Do not use this medicine if you are already taking azathioprine. Together they can give some serious side effects.

It is a bone marrow suppressant. It temporarily reduces your white blood cells and platelets, and so making you susceptible to infections and bleeding. While using this drug you should avoid people with the infection.

Inform your doctor immediately if you notice:

Be careful when using a regular toothbrush, dental floss, or toothpick. Be careful not to cut yourself when you are using sharp objects such as a safety razor or fingernail or toenail cutters.

Do not have any immunization (vaccination) during and after the treatment with this drug without your doctor’s approval. Mercaptopurine may lower your body's resistance and there is a chance you might get the infection the immunization is meant to prevent.

It can aggravate liver diseases.

Inform your doctor if you notice any of these symptoms such as:

Sequential multiple analyzers is a test which measures blood sugar and uric acid level. This test can be affected by Mercaptopurine use.

It may increase your risks of getting cancer. A rare type of cancer called hepatosplenic T-cell lymphoma (HSTCL) is reported in a patient who has Crohn’s disease and is also using this medicine.

Inform your doctor if you have:

  • unusual bleeding
  • bruising
  • weakness
  • swollen lymph nodes in the neck, underarms or groin
  • unexplained weight loss

5 Potential Side Effects

As with many medications, there are several potential side effects associated with Purinethol. Some people may experience none or minor side effects.

Consult with your doctor if they become problematic or frequent:

More common are:

  • Abdominal or stomach pain or tenderness
  • Black, tarry stools
  • Blood in the urine or stools
  • Clay-colored stools
  • A cough or hoarseness
  • Dark urine
  • Decreased appetite
  • Fever or chills
  • Headache
  • Itching
  • Loss of appetite
  • Lower back or side pain
  • Nausea and vomiting
  • Painful or difficult urination
  • Pinpoint red spots on the skin
  • Skin rash
  • Swelling of the feet or lower legs

Less common:

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.

6 Related Clinical Trials