Drug interactions
Cobicistat + Mexiletine
Severity: Major
Cobicistat and Mexiletine: major 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
Cobicistat inhibits CYP3A4 and CYP2D6, both of which contribute to mexiletine metabolism, so mexiletine levels may increase. This raises the risk of neurologic toxicity and proarrhythmia.
What this interaction means in plain words
Cobicistat and Mexiletine 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.
Cobicistat belongs to Miscellaneous; Mexiletine belongs to Cardiovascular.
Why it happens
Cobicistat inhibits CYP2D6 and CYP3A4, reducing mexiletine clearance.
What to do
Monitor ECG and mexiletine concentrations when available, and reduce the mexiletine dose as needed. Watch for tremor, dizziness, nausea and conduction abnormalities.
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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Other interactions of Mexiletine
- Fezolinetant + Mexiletine Contraindicated
- Mexiletine + Pimozide Contraindicated
- Alosetron + Mexiletine Major
- Amiodarone + Mexiletine Major
- Clozapine + Mexiletine Major
- Dofetilide + Mexiletine Major
Other interactions of Cobicistat
- Alfuzosin + Cobicistat Contraindicated
- Apalutamide + Cobicistat Contraindicated
- Cobicistat + Colchicine Contraindicated
- Cobicistat + Dronedarone Contraindicated
- Cobicistat + Eletriptan Contraindicated
- Cobicistat + Eplerenone Contraindicated
Frequently asked questions
Can I take Cobicistat with Mexiletine?
MediHelp rates the interaction as major. Cobicistat and Mexiletine 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. Cobicistat inhibits CYP3A4 and CYP2D6, both of which contribute to mexiletine metabolism, so mexiletine levels may increase. This raises the risk of neurologic toxicity and proarrhythmia.
How serious is the interaction between Cobicistat and Mexiletine?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor ECG and mexiletine concentrations when available, and reduce the mexiletine dose as needed. Watch for tremor, dizziness, nausea and conduction abnormalities.
What other medicines interact with Mexiletine?
MediHelp also lists interactions of Mexiletine with, for example, Fezolinetant, Pimozide, Alosetron. The full list is on the Mexiletine page.
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