Drug interactions
Nafcillin + Sirolimus
Severity: Major
Nafcillin and Sirolimus: 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
Nafcillin can induce CYP3A4 and may lower sirolimus blood concentrations, risking loss of immunosuppression and graft rejection. The effect develops over days and may persist after nafcillin is stopped.
What this interaction means in plain words
Nafcillin and Sirolimus 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.
Why it happens
Nafcillin induces hepatic and intestinal CYP3A4 (and possibly P-gp), increasing sirolimus clearance.
What to do
Monitor sirolimus trough concentrations closely and increase the dose as needed during nafcillin therapy; choose a non-inducing antibiotic if feasible. Readjust the dose after nafcillin is stopped.
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 Sirolimus
- Adenovirus types 4 and 7 live + Sirolimus Contraindicated
- Bcg vaccine live + Sirolimus Contraindicated
- Influenza virus vaccine quadrivalent intranasal + Sirolimus Contraindicated
- Ketoconazole + Sirolimus Contraindicated
- Levoketoconazole + Sirolimus Contraindicated
- Measles mumps and rubella vaccine live + Sirolimus Contraindicated
Frequently asked questions
Can I take Nafcillin with Sirolimus?
MediHelp rates the interaction as major. Nafcillin and Sirolimus 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. Nafcillin can induce CYP3A4 and may lower sirolimus blood concentrations, risking loss of immunosuppression and graft rejection. The effect develops over days and may persist after nafcillin is stopped.
How serious is the interaction between Nafcillin and Sirolimus?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor sirolimus trough concentrations closely and increase the dose as needed during nafcillin therapy; choose a non-inducing antibiotic if feasible. Readjust the dose after nafcillin is stopped.
What other medicines interact with Sirolimus?
MediHelp also lists interactions of Sirolimus with, for example, Adenovirus types 4 and 7 live, Bcg vaccine live, Influenza virus vaccine quadrivalent intranasal. The full list is on the Sirolimus page.
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