6-Mercaptopurine (Purinethol) and Ketamine Therapy | Tovani Health
Purinethol (6-Mercaptopurine) (also: Purixan) — Purine antimetabolite (ALL maintenance, Crohn's disease, autoimmune)
Verdict at Tovani Health
Fully compatible; same allopurinol-interaction story as azathioprine.
6-Mercaptopurine and ketamine have no clinically significant interaction. Used in acute lymphoblastic leukemia maintenance therapy and as a steroid-sparing agent in Crohn's disease and ulcerative colitis. Identical interaction profile to azathioprine — never combine with allopurinol or febuxostat at full dose (xanthine oxidase inhibition causes severe toxicity). TPMT testing is standard.
If you take Purinethol regularly and are considering at-home ketamine therapy, the combination is generally safe at therapeutic doses. This page covers the brief pharmacologic context and what we do at intake.
How Purinethol interacts with ketamine
6-Mercaptopurine is metabolized by TPMT to inactive metabolites or by HGPRT to active thioguanine nucleotides. Xanthine oxidase is the route blocked by allopurinol. No CYP overlap with ketamine.
What we do at intake
Continue as prescribed. Disclose if you're on allopurinol or febuxostat. Recent CBC + LFTs.
Bottom line
6-Mercaptopurine and ketamine have no clinically significant interaction. Used in acute lymphoblastic leukemia maintenance therapy and as a steroid-sparing agent in Crohn's disease and ulcerative colitis. Identical interaction profile to azathioprine — never combine with allopurinol or febuxostat at full dose (xanthine oxidase inhibition causes severe toxicity). TPMT testing is standard.
Ready to find out if at-home ketamine fits your situation?
We’ll note that you’re on Purinethol (6-Mercaptopurine) at intake. The eligibility check takes 5 minutes and gives you an honest answer about whether at-home ketamine fits your specific situation.
FL and NJ residents only. Benjamin Soffer, DO — Tovani Health.
Clinically reviewed
Reviewed by Benjamin Soffer, DO on May 22, 2026. Dr. Soffer is a board-certified physician (American Board of Internal Medicine) licensed in Florida and New Jersey, prescribing at-home ketamine therapy through Tovani Health.
This page is general information about how this medication interacts with at-home ketamine therapy at Tovani Health. It is not a substitute for medical advice from your prescribing physician about your specific situation. Always discuss medication changes with the doctor who prescribed them.