Drug interactions
Deflazacort + Fosamprenavir
Severity: Major
Deflazacort and Fosamprenavir: major interaction.
Last updated Sources: US FDA label
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
Fosamprenavir (as amprenavir) inhibits CYP3A4, particularly when boosted with ritonavir, and increases exposure to the active metabolite of deflazacort. Corticosteroid adverse effects such as adrenal suppression, hyperglycemia and infection may be increased.
What this interaction means in plain words
Deflazacort and Fosamprenavir 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
Inhibition of CYP3A4 reduces clearance of deflazacort's active metabolite.
What to do
Give one-third of the usual deflazacort dose during coadministration. Monitor for glucocorticoid toxicity.
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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References
Other interactions of Deflazacort
- Adenovirus types 4 and 7 live + Deflazacort Contraindicated
- Bcg vaccine live + Deflazacort Contraindicated
- Deflazacort + Influenza virus vaccine quadrivalent intranasal Contraindicated
- Deflazacort + Measles mumps and rubella vaccine Contraindicated
- Deflazacort + Measles mumps and rubella vaccine live Contraindicated
- Deflazacort + Measles mumps rubella and varicella vaccine live Contraindicated
Frequently asked questions
Can I take Deflazacort with Fosamprenavir?
MediHelp rates the interaction as major. Deflazacort and Fosamprenavir 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. Fosamprenavir (as amprenavir) inhibits CYP3A4, particularly when boosted with ritonavir, and increases exposure to the active metabolite of deflazacort. Corticosteroid adverse effects such as adrenal suppression, hyperglycemia and infection may be increased.
How serious is the interaction between Deflazacort and Fosamprenavir?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Give one-third of the usual deflazacort dose during coadministration. Monitor for glucocorticoid toxicity.
What other medicines interact with Deflazacort?
MediHelp also lists interactions of Deflazacort with, for example, Adenovirus types 4 and 7 live, Bcg vaccine live, Influenza virus vaccine quadrivalent intranasal. The full list is on the Deflazacort page.
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