Drug Interaction Report

Using mercaptopurine together with trimethoprim may increase your risk of infections. Call your doctor at once if you have a fever, chills, sore throat, body aches, weakness, muscle pain, easy bruising or bleeding, mouth sores, pale stools, darkened urine, or severe nausea, vomiting, and diarrhea. You may need a dose adjustment or special test if you use both medications. It is important to tell your doctor about all other medications you use, including vitamins and herbs. Do not stop using any medications without first talking to your doctor.

You may experience reduced absorption of mercaptopurine in the presence of food. Take mercaptopurine on an empty stomach 1 hour before or 2 hours after a meal. This will make it easier for your body to absorb the medication.