Drug interactions
Clarithromycin + Fosaprepitant
Severity: Moderate
Clarithromycin and Fosaprepitant: 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
Fosaprepitant is converted to aprepitant, a CYP3A4 substrate, and clarithromycin can raise aprepitant exposure. Single-dose fosaprepitant exposure is brief, so the clinical effect is usually modest and mainly increases adverse effects such as fatigue, headache and GI upset.
What this interaction means in plain words
Clarithromycin and Fosaprepitant 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 belongs to Anti Bacterial; Fosaprepitant belongs to Gastrointestinal Tract.
Why it happens
Clarithromycin inhibits CYP3A4 metabolism of aprepitant, increasing its plasma concentrations.
What to do
No routine dose change is needed, but monitor for aprepitant-related adverse effects. Consider a non-inhibiting antibiotic if repeated dosing is planned.
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
Other interactions of Fosaprepitant
- Flibanserin + Fosaprepitant Contraindicated
- Fosaprepitant + Pimozide Contraindicated
- Alprazolam + Fosaprepitant Moderate
- Amiodarone + Fosaprepitant Moderate
- Amobarbital + Fosaprepitant Moderate
- Apalutamide + Fosaprepitant Moderate
Frequently asked questions
Can I take Clarithromycin with Fosaprepitant?
MediHelp rates the interaction as moderate. Clarithromycin and Fosaprepitant 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. Fosaprepitant is converted to aprepitant, a CYP3A4 substrate, and clarithromycin can raise aprepitant exposure. Single-dose fosaprepitant exposure is brief, so the clinical effect is usually modest and mainly increases adverse effects such as fatigue, headache and GI upset.
How serious is the interaction between Clarithromycin and Fosaprepitant?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: No routine dose change is needed, but monitor for aprepitant-related adverse effects. Consider a non-inhibiting antibiotic if repeated dosing is planned.
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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