Drug interactions
Isavuconazole + Ritonavir
Severity: Contraindicated
Isavuconazole and Ritonavir: contraindicated 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
High-dose ritonavir can induce metabolism of isavuconazole and lower its exposure, whereas lower doses act as a CYP3A4 inhibitor and may raise it. The net effect depends on dose and can compromise efficacy or increase toxicity.
What this interaction means in plain words
Isavuconazole and Ritonavir are not normally used together. Taking them at the same time is expected to cause harm or make one of them unsafe, so a different medicine is usually chosen for one of the two.
Isavuconazole belongs to Anti Fungals; Ritonavir belongs to Anti Virals.
Why it happens
Dose-dependent mixed CYP3A4 effects of ritonavir; high doses induce isavuconazole clearance.
What to do
Avoid high-dose ritonavir with isavuconazole. With low-dose boosting, monitor isavuconazole levels, response and adverse effects.
What to ask your pharmacist
- Is there an alternative to one of these two medicines for me?
- If both are essential, who is monitoring me and how often?
- Which symptoms mean I should stop and seek help straight away?
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Other interactions of Isavuconazole
- Carbamazepine + Isavuconazole Contraindicated
- Efavirenz + Isavuconazole Contraindicated
- Etravirine + Isavuconazole Contraindicated
- Isavuconazole + Ketoconazole Contraindicated
- Isavuconazole + Phenobarbitone Contraindicated
- Isavuconazole + Phenytoin Contraindicated
Other interactions of Ritonavir
- Alfuzosin + Ritonavir Contraindicated
- Amiodarone + Ritonavir Contraindicated
- Avanafil + Ritonavir Contraindicated
- Colchicine + Ritonavir Contraindicated
- Dronedarone + Ritonavir Contraindicated
- Eletriptan + Ritonavir Contraindicated
Frequently asked questions
Can I take Isavuconazole with Ritonavir?
MediHelp rates the interaction as contraindicated. Isavuconazole and Ritonavir are not normally used together. Taking them at the same time is expected to cause harm or make one of them unsafe, so a different medicine is usually chosen for one of the two. High-dose ritonavir can induce metabolism of isavuconazole and lower its exposure, whereas lower doses act as a CYP3A4 inhibitor and may raise it. The net effect depends on dose and can compromise efficacy or increase toxicity.
How serious is the interaction between Isavuconazole and Ritonavir?
MediHelp rates it contraindicated, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid high-dose ritonavir with isavuconazole. With low-dose boosting, monitor isavuconazole levels, response and adverse effects.
What other medicines interact with Isavuconazole?
MediHelp also lists interactions of Isavuconazole with, for example, Carbamazepine, Efavirenz, Etravirine. The full list is on the Isavuconazole page.
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