Table 4.
Important Drug Interactions of Thiopurines
| Name of the drug | Possible mechanism | Outcome |
|---|---|---|
| Allopurinol and Febuxostat (XO inhibitors) | Inhibition of XO and shunting 6-MP to 6-TGN formation | Myelosuppression |
| 5-Aminosalicylates | TPMT inhibition | Myelosuppression |
| Warfarin | Possibly increased metabolism/decreased absorption | Decreased warfarin efficacy |
| ACE inhibitors | Poorly understood | Myelosuppression and anemia |
| Loop diuretics | TPMT inhibition | Myelosuppression |
| Ribavirin | IMPDH inhibition | Myelosuppression |
| Chemotherapeutic agents | Likely additive effect on cytotoxicity of sinusoidal cells | Sinusoidal obstruction syndrome/veno-occlusive disease |
XO, xanthine oxidase; ACE, angiotensin converting enzyme; 6-MP, 6-mercaptopurine; 6-TGN, 6-thioguanine nucleotides; TPMT, thiopurine-S-methyltransferase; IMPDH, inosine monophosphate dehydrogenase.