Drug interactions
Mercaptopurine + Mycophenolate mofetil
Severity: Major
Mercaptopurine and Mycophenolate mofetil: major interaction.
Last updated
For healthcare professionals — reference only. This page is a brief summary, not medical advice and not a substitute for official labeling or clinical judgement. Always verify before prescribing or dispensing.
Summary
Both drugs suppress bone marrow and lymphocyte function, so combining them raises the risk of leukopenia and infection. Mycophenolate inhibits inosine monophosphate dehydrogenase in the same purine synthesis pathway, which makes additive toxicity plausible.
What this interaction means in plain words
Mercaptopurine and Mycophenolate mofetil can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for.
Mercaptopurine belongs to Oncology; Mycophenolate mofetil belongs to Miscellaneous.
Why it happens
Additive myelosuppression and immunosuppression through overlapping effects on purine metabolism.
What to do
Avoid the combination where possible. If used together, monitor complete blood counts frequently and reduce the dose of one or both drugs for leukopenia.
What to ask your pharmacist
- Does the benefit of taking both outweigh the risk in my case?
- Do I need any blood test, ECG or other check while on both?
- What early warning signs should I watch for, and what should I do if they appear?
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Other interactions of Mycophenolate mofetil
- Adenovirus types 4 and 7 live + Mycophenolate mofetil Contraindicated
- Bcg vaccine live + Mycophenolate mofetil Contraindicated
- Influenza virus vaccine quadrivalent intranasal + Mycophenolate mofetil Contraindicated
- Measles mumps and rubella vaccine live + Mycophenolate mofetil Contraindicated
- Measles mumps rubella and varicella vaccine live + Mycophenolate mofetil Contraindicated
- Measles vaccine + Mycophenolate mofetil Contraindicated
Other interactions of Mercaptopurine
- Adenovirus types 4 and 7 live + Mercaptopurine Contraindicated
- Azathioprine + Mercaptopurine Contraindicated
- Bcg vaccine live + Mercaptopurine Contraindicated
- Febuxostat + Mercaptopurine Contraindicated
- Influenza virus vaccine quadrivalent intranasal + Mercaptopurine Contraindicated
- Mercaptopurine + Smallpox vaccine live Contraindicated
Frequently asked questions
Can I take Mercaptopurine with Mycophenolate mofetil?
MediHelp rates the interaction as major. Mercaptopurine and Mycophenolate mofetil can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for. Both drugs suppress bone marrow and lymphocyte function, so combining them raises the risk of leukopenia and infection. Mycophenolate inhibits inosine monophosphate dehydrogenase in the same purine synthesis pathway, which makes additive toxicity plausible.
How serious is the interaction between Mercaptopurine and Mycophenolate mofetil?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid the combination where possible. If used together, monitor complete blood counts frequently and reduce the dose of one or both drugs for leukopenia.
What other medicines interact with Mycophenolate mofetil?
MediHelp also lists interactions of Mycophenolate mofetil with, for example, Adenovirus types 4 and 7 live, Bcg vaccine live, Influenza virus vaccine quadrivalent intranasal. The full list is on the Mycophenolate mofetil page.
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