Drug interactions
Haemophilus influenzae type b vaccine + Mercaptopurine
Severity: Moderate
Haemophilus influenzae type b vaccine and Mercaptopurine: moderate 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
Mercaptopurine can diminish the antibody response to the Hib conjugate vaccine. Patients may remain inadequately protected against invasive Hib disease. The vaccine is non-live and safe to give, but its efficacy may be lower.
What this interaction means in plain words
Haemophilus influenzae type b vaccine and Mercaptopurine can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken.
Why it happens
Immunosuppression from purine antimetabolite activity impairs antigen-specific antibody production.
What to do
Vaccinate at least 2 weeks before starting mercaptopurine when feasible. If given during therapy, consider revaccination once immune function has recovered after treatment is stopped.
What to ask your pharmacist
- Should I take them at different times of day?
- Does the dose of either medicine need to change?
- Is there anything I should avoid, such as alcohol or certain foods, while on both?
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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 Haemophilus influenzae type b vaccine with Mercaptopurine?
MediHelp rates the interaction as moderate. Haemophilus influenzae type b vaccine and Mercaptopurine can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken. Mercaptopurine can diminish the antibody response to the Hib conjugate vaccine. Patients may remain inadequately protected against invasive Hib disease. The vaccine is non-live and safe to give, but its efficacy may be lower.
How serious is the interaction between Haemophilus influenzae type b vaccine and Mercaptopurine?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Vaccinate at least 2 weeks before starting mercaptopurine when feasible. If given during therapy, consider revaccination once immune function has recovered after treatment is stopped.
What other medicines interact with Mercaptopurine?
MediHelp also lists interactions of Mercaptopurine with, for example, Adenovirus types 4 and 7 live, Azathioprine, Bcg vaccine live. The full list is on the Mercaptopurine page.
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