6-mercaptopurine + methylprednisolone

This is a combination of two pharmaceutical agents:

• 6-mercaptopurine (6-MP) is an antimetabolite and immunosuppressive small molecule that inhibits purine synthesis, thereby suppressing DNA and RNA synthesis in rapidly dividing cells. It acts primarily by being converted to thioinosinic acid (TIMP), which inhibits several enzymes involved in the de novo pathway for purine ribonucleotide synthesis, including hypoxanthine-guanine phosphoribosyltransferase, inosine monophosphate dehydrogenase, and amidophosphoribosyltransferase.
• Methylprednisolone is a synthetic glucocorticoid corticosteroid with potent anti-inflammatory and immunosuppressive properties. It binds to the glucocorticoid receptor to modulate gene expression and suppress immune responses.

The combination may be used off-label or as part of multi-drug regimens for conditions such as acute lymphoblastic leukemia (ALL) or inflammatory bowel disease (IBD), particularly Crohn’s disease. The rationale for combining these drugs is to achieve synergistic immunosuppression—methylprednisolone provides rapid anti-inflammatory effects while 6-MP offers long-term maintenance of remission. This approach can reduce steroid requirements over time.