Azathioprine
Azathioprine. Prodrug of 6-mercaptopurine — incorporated into DNA as thioguanine nucleotides causing immunosuppression. TPMT polymorphism (~10%… Oral half-life 0.8 h.
Prodrug of 6-mercaptopurine — incorporated into DNA as thioguanine nucleotides causing immunosuppression. TPMT polymorphism (~10% intermediate, ~0.3% deficient) drives marked toxicity variability — pre-treatment TPMT/NUDT15 genotyping standard. IBD + autoimmune + steroid-sparing transplant maintenance.
PK: F 0.47 is verbatim but is 6-MERCAPTOPURINE bioavailability after oral azathioprine, not azathioprine own, and is now labelled as such. The stored 5 h was wrong by an order of magnitude: the parent terminal half-life is 50 minutes and 6-mercaptopurine 74 minutes (PMID:3957504), and 0.83 h is now stored. ka 1 /h and V 60 L dropped as unsourced. EFFECT IS DECOUPLED FROM PLASMA: the active species are thioguanine nucleotides that persist inside cells for weeks, so no parameter here represents the duration of immunosuppression.
Pharmacokinetics
- Oral — t½ 50 min · F 47%
Sources: PMID:8881811, PMID:3957504