Drug interactions
Clarithromycin + Nirmatrelvir / ritonavir
Severity: Moderate
Clarithromycin and Nirmatrelvir / ritonavir: 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
Ritonavir-boosted nirmatrelvir raises clarithromycin concentrations, increasing the risk of QT prolongation and other adverse effects, especially with renal impairment. Clarithromycin also may raise nirmatrelvir and ritonavir exposure.
What this interaction means in plain words
Clarithromycin and Nirmatrelvir / ritonavir 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
Ritonavir inhibits CYP3A4 and P-gp, reducing clarithromycin clearance.
What to do
Limit clarithromycin to no more than 1,000 mg daily and reduce the dose in renal impairment; monitor ECG if risk factors for QT prolongation exist.
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 Nirmatrelvir / ritonavir?
MediHelp rates the interaction as moderate. Clarithromycin and Nirmatrelvir / ritonavir 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. Ritonavir-boosted nirmatrelvir raises clarithromycin concentrations, increasing the risk of QT prolongation and other adverse effects, especially with renal impairment. Clarithromycin also may raise nirmatrelvir and ritonavir exposure.
How serious is the interaction between Clarithromycin and Nirmatrelvir / ritonavir?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Limit clarithromycin to no more than 1,000 mg daily and reduce the dose in renal impairment; monitor ECG if risk factors for QT prolongation exist.
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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