How to use
Mercaptopurine should be taken orally once a day at approximately the same time with a full glass of water. It is preferable to take Mercaptopurine on an empty stomach (1 hour before or 2 hours after a meal).
The amount and dosage schedule will be determined by your doctor and will depend on various factors, such as your age, height and weight, your general health and what type of cancer or condition is being treated.

Overdose
Possible symptoms of a Mercaptopurine overdose include:

• Sudden or severe nausea or vomiting
• Sudden or severe diarrhea
• Dark urine
• Severe abdominal pain
• Yellowing eyes/skin

If you suspect you have taken too much Mercaptopurine, contact your local poison control center or the emergency medical services immediately.

Missed Dose
If you miss a dose of Mercaptopurine, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not try to make up for a missed dose by doubling up.

Notes
Laboratory and/or medical tests (e.g., complete blood count, liver function tests) should be performed periodically to monitor your progress or check for side effects.
Do not share this medication with others, as they may have a problem that is not effectively treated by this drug.

Storage
Store Mercaptopurine at room temperature, between 59 and 86 degrees F (15 and 30 degrees C), away from heat and moisture. KEEP THIS AND ALL OTHER MEDICATION OUT OF REACH OF CHILDREN.

Important Note
The above information is intended to supplement, not substitute for, the expertise and judgment of your physician, pharmacist or other healthcare professional. It should not be construed that the taking of this medication is safe, appropriate or effective for you.

Precautions
Inform your doctor before taking Mercaptopurine, if you suffer or have suffered from any of the following:

• An allergic reaction to Mercaptopurine
• Pancreatitis (inflammation of the pancreas)
• A liver or kidney disease
• Gout
• Suppressed bone marrow (tissue filling the empty spaces inside the bone)

Mercaptopurine is classed as Pregnancy Category D by the FDA, which means it could potentially harm an unborn baby. You should not use this medication when pregnant. While taking Mercaptopurine, you should use an adequate method of contraception.
It is not yet know whether Mercaptopurine passes into breast milk, so you should discuss the use of Mercaptopurine with your doctor when breastfeeding.

Drug Interactions
Before using Mercaptopurine, inform you doctor if you are using any of the following medications:

• A blood thinner such as Warfarin
• Allopurinal (medication against gout)
• Medication that reduces the function of the liver (e.g. doxorubicin)
• Non-steroidal anti-inflammatory drugs (NSAIDs), such as aspirin, ibuprofen (Advil, Motrin), naproxen (Aleve, Naprosyn) and many others
• Ticlopidine (Ticlid)
• Clopidogrel (Plavix)

This is only a partial list and other drugs may interact with Mercaptopurine. Tell your doctor about all the prescription and over-the-counter medications you use. This includes vitamins, minerals, herbal products, and drugs prescribed by other doctors. Do not start using a new medication without telling your doctor.

When taking Mercaptopurine, you may experience any of the following common side effects:

• A low blood count
• Liver toxicity (within 2 months of starting treatment)

Inform your health care provider if you experience any of the following less common side effects:

• Nausea and vomiting, diarrhea, poor appetite
• Mouth sores
• Loss of fertility
• Skin rash, dry skin, itching, discoloration of the skin (hyperpigmentation)
• Darkening of the skin where previous radiation treatment has been given)
• Yellowing of the skin or eyes
• Unusual bleeding or bruising
• Black or tarry stools, or blood in your stools or urine
• Extreme fatigue
• Signs of infection such as redness or swelling, pain on swallowing, coughing up mucous, or painful urination

Seek emergency medical attention if you experience the following side effect:

• Fever of 100.5º F (38º C) or higher, chills (possible signs of infection)

Notify your doctor if you experience any other side effects than the ones mentioned above, especially if they are bothersome.