Drug interactions
Cobimetinib + Fluconazole
Severity: Major
Cobimetinib and Fluconazole: major interaction.
Last updated Sources: Health Canada product monograph
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
Fluconazole, a moderate CYP3A4 inhibitor, can raise cobimetinib concentrations and increase the risk of adverse effects such as serous retinopathy, rhabdomyolysis, hemorrhage, liver injury and diarrhea.
What this interaction means in plain words
Cobimetinib and Fluconazole 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.
Cobimetinib belongs to Oncology; Fluconazole belongs to Anti Fungals.
Why it happens
Inhibition of CYP3A4-mediated metabolism of cobimetinib by fluconazole.
What to do
Prefer a non-CYP3A-inhibiting antifungal. If short-term use (14 days or less) is unavoidable, reduce cobimetinib from 60 mg to 20 mg and resume the usual dose after stopping fluconazole, monitoring for 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 Fluconazole
- Dihydroergotamine intranasal + Fluconazole Contraindicated
- Dihydroergotamine + Fluconazole Contraindicated
- Dofetilide + Fluconazole Contraindicated
- Domperidone + Fluconazole Contraindicated
- Dronedarone + Fluconazole Contraindicated
- Erythromycin + Fluconazole Contraindicated
Other interactions of Cobimetinib
- Cobimetinib + Efavirenz Contraindicated
- Cobimetinib + Posaconazole Contraindicated
- Amobarbital + Cobimetinib Major
- Apalutamide + Cobimetinib Major
- Aprepitant + Cobimetinib Major
- Bosentan + Cobimetinib Major
Frequently asked questions
Can I take Cobimetinib with Fluconazole?
MediHelp rates the interaction as major. Cobimetinib and Fluconazole 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. Fluconazole, a moderate CYP3A4 inhibitor, can raise cobimetinib concentrations and increase the risk of adverse effects such as serous retinopathy, rhabdomyolysis, hemorrhage, liver injury and diarrhea.
How serious is the interaction between Cobimetinib and Fluconazole?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Prefer a non-CYP3A-inhibiting antifungal. If short-term use (14 days or less) is unavoidable, reduce cobimetinib from 60 mg to 20 mg and resume the usual dose after stopping fluconazole, monitoring for toxicity.
What other medicines interact with Fluconazole?
MediHelp also lists interactions of Fluconazole with, for example, Dihydroergotamine intranasal, Dihydroergotamine, Dofetilide. The full list is on the Fluconazole page.
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