Drug interactions
Cimetidine + Fluphenazine
Severity: Minor
Cimetidine and Fluphenazine: minor 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 increase fluphenazine concentrations and thereby the risk of sedation and extrapyramidal effects. Evidence is limited and the effect is usually small.
What this interaction means in plain words
Cimetidine and Fluphenazine have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised.
Cimetidine belongs to Gastrointestinal Tract; Fluphenazine belongs to Central Nervous System.
Why it happens
Cimetidine inhibits CYP2D6, the main enzyme metabolizing fluphenazine.
What to do
Monitor for extrapyramidal symptoms and sedation, and lower the fluphenazine dose if they emerge.
What to ask your pharmacist
- Is there anything I should notice while taking both?
- Do I need to tell my doctor at the next visit?
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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 Fluphenazine
- Arsenic trioxide + Fluphenazine Contraindicated
- Dofetilide + Fluphenazine Contraindicated
- Fluphenazine + Ibutilide Contraindicated
- Fluphenazine + Pimozide Contraindicated
- Adagrasib + Fluphenazine Major
- Alfentanil + Fluphenazine Major
Frequently asked questions
Can I take Cimetidine with Fluphenazine?
MediHelp rates the interaction as minor. Cimetidine and Fluphenazine have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised. Cimetidine may increase fluphenazine concentrations and thereby the risk of sedation and extrapyramidal effects. Evidence is limited and the effect is usually small.
How serious is the interaction between Cimetidine and Fluphenazine?
MediHelp rates it minor, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor for extrapyramidal symptoms and sedation, and lower the fluphenazine dose if they emerge.
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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