Drug interactions
Cimetidine + Mexiletine
Severity: Moderate
Cimetidine and Mexiletine: 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
Cimetidine may alter mexiletine clearance, with reports of both increased and unchanged levels. Elevated mexiletine concentrations can cause tremor, dizziness, nausea and arrhythmia.
What this interaction means in plain words
Cimetidine and Mexiletine 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.
Cimetidine belongs to Gastrointestinal Tract; Mexiletine belongs to Cardiovascular.
Why it happens
Cimetidine inhibits CYP2D6 and CYP1A2, which metabolize mexiletine.
What to do
Monitor for mexiletine toxicity and ECG changes, and consider checking serum levels; use famotidine as an alternative where possible.
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 Cimetidine
- Cimetidine + Dofetilide Contraindicated
- Cimetidine + Fezolinetant Contraindicated
- Alfentanil + Cimetidine Major
- Atazanavir + Cimetidine Major
- Carmustine + Cimetidine Major
- Cimetidine + Citalopram Major
Other interactions of Mexiletine
- Fezolinetant + Mexiletine Contraindicated
- Mexiletine + Pimozide Contraindicated
- Alosetron + Mexiletine Major
- Amiodarone + Mexiletine Major
- Clozapine + Mexiletine Major
- Cobicistat + Mexiletine Major
Frequently asked questions
Can I take Cimetidine with Mexiletine?
MediHelp rates the interaction as moderate. Cimetidine and Mexiletine 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. Cimetidine may alter mexiletine clearance, with reports of both increased and unchanged levels. Elevated mexiletine concentrations can cause tremor, dizziness, nausea and arrhythmia.
How serious is the interaction between Cimetidine and Mexiletine?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor for mexiletine toxicity and ECG changes, and consider checking serum levels; use famotidine as an alternative where possible.
What other medicines interact with Cimetidine?
MediHelp also lists interactions of Cimetidine with, for example, Dofetilide, Fezolinetant, Alfentanil. The full list is on the Cimetidine page.
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