Mercaptopurine is an anti-cancer ("antineoplastic" or "cytotoxic") chemotherapy drug. This medication is classified as an "antimetabolite." (For more detail, see "How this drug works" section below).
What this drug is used for:
Acute lymphoblastic leukemia (ALL)
Note: If a drug has been approved for one use, physicians may elect to use this same drug for other problems if they believe it may be helpful.
How this drug is given:
As a tablet by mouth. Comes in one tablet size (50mg).
Take as a daily dose at the same time each day. Preferable to take on an empty stomach (1 hour before or 2 hours after meals).
The amount of mercaptopurine that you will receive depends on many factors, including your height and weight, your general health or other health problems, and the type of cancer or condition being treated. Your doctor will determine your dose and schedule.
Side effects:
Important things to remember about the side effects of mercaptopurine:
Most people do not experience all of the side effects listed.
Side effects are often predictable in terms of their onset and duration.
Side effects are almost always reversible and will go away after treatment is complete.
There are many options to help minimize or prevent side effects.
There is no relationship between the presence or severity of side effects and the effectiveness of the medication.
The following side effects are common (occurring in greater than 30%) for patients taking mercaptopurine:
Low blood counts. Your white and red blood cells and platelets may temporarily decrease. This can put you at increased risk for infection, anemia and/or bleeding.
Nadir: Meaning low point, nadir is the point in time between chemotherapy cycles in which you experience low blood counts.
Onset: 7-10 days
Nadir: 14 days
Recovery: 21-28 days
Liver toxicity. (see liver problems) Increased bilirubin, increased liver enzymes, jaundice, abdominal swelling (ascites). Increased with higher doses of drug. Usually occurs within 2 months of treatment.
These side effects are less common side effects (occurring in about 10-29%) of patients receiving mercaptopurine:
Nausea and vomiting
Poor appetite
Diarrhea. (rare - usually seen with higher dose)
Mouth sores (rare - usually seen with higher dose)
Loss of fertility. Meaning, your ability to conceive or father a child may be affected by mercaptopurine. Discuss this issue with your health care provider.
Skin rash, dry skin, itching, discoloration of the skin (hyperpigmentation) (uncommon) (see skin reactions).
Darkening of the skin where previous radiation treatment has been given. (radiation recall - see skin reactions) (rare).
Not all side effects are listed above. Some that are rare (occurring in less than 10% of patients) are not listed here. However, you should always inform your health care provider if you experience any unusual symptoms.
When to contact your doctor or health care provider:
Contact your health care provider immediately, day or night, if you should experience any of the following symptoms:
Fever of 100.4° F (38° C) or higher, chills (possible signs of infection)
The following symptoms require medical attention, but are not an emergency. Contact your health care provider within 24 hours of noticing any of the following:
Yellowing of the skin or eyes
Unusual bleeding or bruising
Black or tarry stools, or blood in your stools or urine
Extreme fatigue (unable to carry on self-care activities)
Nausea (interferes with ability to eat and unrelieved with prescribed medication)
Vomiting (vomiting more than 4-5 times in a 24 hour period)
Diarrhea (4-6 episodes in a 24-hour period)
Mouth sores (painful redness, swelling or ulcers)
Signs of infection such as redness or swelling, pain on swallowing, coughing up mucous, or painful urination.