Drug interactions
Clarithromycin + Fosamprenavir
Severity: Moderate
Clarithromycin and Fosamprenavir: 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
Clarithromycin and amprenavir (the active form of fosamprenavir) may raise each other's concentrations through CYP3A4 effects. This can increase adverse effects of both drugs, including QT-related and gastrointestinal effects.
What this interaction means in plain words
Clarithromycin and Fosamprenavir 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
Mutual CYP3A4 inhibition reduces metabolism of both drugs.
What to do
Monitor for adverse effects and ECG changes, and reduce the clarithromycin dose in renal impairment. Consider azithromycin as an alternative where clinically appropriate.
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 Clarithromycin
- Astemizole + Clarithromycin Contraindicated
- Avanafil + Clarithromycin Contraindicated
- Cisapride + Clarithromycin Contraindicated
- Clarithromycin + Colchicine Contraindicated
- Clarithromycin + Conivaptan Contraindicated
- Clarithromycin + Dihydroergotamine Contraindicated
Frequently asked questions
Can I take Clarithromycin with Fosamprenavir?
MediHelp rates the interaction as moderate. Clarithromycin and Fosamprenavir 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. Clarithromycin and amprenavir (the active form of fosamprenavir) may raise each other's concentrations through CYP3A4 effects. This can increase adverse effects of both drugs, including QT-related and gastrointestinal effects.
How serious is the interaction between Clarithromycin and Fosamprenavir?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor for adverse effects and ECG changes, and reduce the clarithromycin dose in renal impairment. Consider azithromycin as an alternative where clinically appropriate.
What other medicines interact with Clarithromycin?
MediHelp also lists interactions of Clarithromycin with, for example, Astemizole, Avanafil, Cisapride. The full list is on the Clarithromycin page.
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