Pathway of azathioprine metabolism
| Azathioprine | ||
| ⇓ | ||
| 6-Mercaptopurine | ||
| ⇓ | ⇓ | ⇓ |
| Thiopurine methyltransferase | Xanthine oxidase | Hypoxanthine-guanine |
| (TPMT) | phophoribosyl-transferase | |
| ⇓ | ⇓ | ⇓ |
| 6-Methyl thiopurine | 6-Thiouric acid | Several active |
| mercaptopurine | metabolites including | |
| 6-Thioguanine nucleotides |