Mercaptopurine (Purixan)

The basics

Mercaptopurine is an FDA-approved treatment used alone or with other chemotherapy drugs for lymphocytic leukemia (ALL; also called acute lymphoblastic leukemia and acute lymphatic leukemia; a type of cancer that begins in the white blood cells).

Mercaptopurine falls in a class of purine antagonists medications. It works by stopping the growth of cancer cells.

Let us walk you through the key things you need to know about mercaptopurine.

How should I take mercaptopurine (Purixan)?

Ankr helps take oral chemotherapy on time

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. Take mercaptopurine exactly as directed. Do not take more or less of it or more often than your Doctor prescribes.

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.

Continue to take mercaptopurine even if you feel well. Do not stop taking mercaptopurine without talking to your doctor. You can help them by tracking your side effects in Ankr.

What are the side effects of mercaptopurine (Purixan)?

Common side effects

Serious side effects

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 or by phone (1-800-332-1088).

Use the free Ankr platform or Ankr app to track your symptoms.

What special precautions should I follow?

Before taking mercaptopurine (Purixan)

  • tell your doctor about your allergies
  • tell your doctor about other intakes
  • tell your doctor if you have or ever had any other disease, symptom, or treatment.
  • tell your doctor if you are pregnant, plan to become pregnant, or are breastfeeding. You should use birth control to avoid pregnancy during your treatment with mercaptopurine.

While you are on mercaptopurine (Purixan)

  • If you become pregnant while taking mercaptopurine, call your doctor immediately. Mercaptopurine may harm the fetus.
  • if you are having surgery, including dental surgery, tell the doctor or dentist that you are taking mercaptopurine.
  • do not have any vaccinations without talking to your doctor.

I forgot a dose. What should I do?

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.

In case of an emergency/overdose

In case of overdose, call the poison control helpline at 1-800-222-1222. Information is also available online at 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:

How should I safely store and dispose of mercaptopurine (Purixan)?

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).

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 ( for more information if you do not have access to a take-back program.

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.

What special dietary instructions should I follow?

Unless your doctor tells you otherwise, continue your normal diet.

Brand names

  • Purinethol®
  • Purixan®

Other names

  • 6-MP

Last Revised – 06/18/2023, FDA updated- 07/19/2022, SG

Get 24×7 support for mercaptopurine (Purixan)

Don’t go through your cancer journey alone. Use Ankr to:
(1) find the best treatment for your cancer, and
(2) get advanced warning to cut side effects by upto 52%

Sign up for a free 30-day trial now


Did you like this content?

Tell us how we can improve this post?

DISCLAIMER: No part of this content constitutes medical advice, opinion, or should be used for medical decision making without consultation with a licenced medical practitioner and under a patient-provider relationship. All information on the website is provided without any claims of accuracy. For full terms and conditions, visit this link. Content curated by the Ankr team.

↑ Back to top