Drug interactions
Cimetidine + Lidocaine
Severity: Moderate
Cimetidine and Lidocaine: 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 reduces hepatic clearance of lidocaine and can raise its plasma concentrations. This may lead to lidocaine toxicity such as dizziness, confusion, seizures or arrhythmia, especially with infusions.
What this interaction means in plain words
Cimetidine and Lidocaine 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; Lidocaine belongs to Cardiovascular.
Why it happens
Cimetidine inhibits hepatic CYP enzymes (including CYP1A2 and CYP3A4) and may reduce hepatic blood flow, decreasing lidocaine metabolism.
What to do
Monitor for signs of lidocaine toxicity and consider reducing the infusion rate, with plasma level monitoring in prolonged therapy. Consider famotidine as an alternative acid suppressant.
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 Lidocaine
- Bupivacaine liposome + Lidocaine Major
- Disopyramide + Lidocaine Major
- Ex vivo expanded autologous human corneal epithelial cells containing stem cells + Lidocaine Major
- Lidocaine + Nirmatrelvir / ritonavir Major
- Lidocaine + Ombitasvir / paritaprevir / ritonavir and dasabuvir Major
- Lidocaine + Pimozide Major
Frequently asked questions
Can I take Cimetidine with Lidocaine?
MediHelp rates the interaction as moderate. Cimetidine and Lidocaine 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 reduces hepatic clearance of lidocaine and can raise its plasma concentrations. This may lead to lidocaine toxicity such as dizziness, confusion, seizures or arrhythmia, especially with infusions.
How serious is the interaction between Cimetidine and Lidocaine?
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 signs of lidocaine toxicity and consider reducing the infusion rate, with plasma level monitoring in prolonged therapy. Consider famotidine as an alternative acid suppressant.
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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