Drug Interaction Report

MONITOR: Coadministration with drugs that are subject to substantial renal clearance such as trimethoprim/sulfamethoxazole and nonsteroidal anti-inflammatory drugs (NSAIDs) may result in delayed clearance of pralatrexate. The mechanism is competitive inhibition of renal excretion, as approximately 34% of pralatrexate is eliminated unchanged by the kidney.

MANAGEMENT: Caution is advised if pralatrexate is prescribed in combination with trimethoprim/sulfamethoxazole or NSAIDs. Complete blood cell counts as well as renal and hepatic function should be closely monitored. Treatment interruption or dose reduction of pralatrexate may be required if toxicities such as mucositis, myelosuppression, or liver enzyme abnormalities develop. Patients should be advised to contact their physician if they develop oral ulcers, painful swallowing, vomiting, diarrhea, and/or signs and symptoms of myelosuppression such as pallor, dizziness, fatigue, lethargy, fainting, easy bruising or bleeding, or signs of infection such as fever, chills, sore throat, body aches, and other influenza-like symptoms.

GENERALLY AVOID: The concurrent use of aspirin or nonsteroidal anti-inflammatory drugs (NSAIDs) and ethanol may lead to gastrointestinal (GI) blood loss. The mechanism may be due to a combined local effect as well as inhibition of prostaglandins leading to decreased integrity of the GI lining.

MANAGEMENT: Patients should be counseled on this potential interaction and advised to refrain from alcohol consumption while taking aspirin or NSAIDs.