Drug interactions
Cimetidine + Olanzapine
Severity: Minor
Cimetidine and Olanzapine: 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 slightly increase olanzapine exposure. The clinical effect is usually small, though sedation or orthostasis could increase.
What this interaction means in plain words
Cimetidine and Olanzapine 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; Olanzapine belongs to Central Nervous System.
Why it happens
Cimetidine inhibits CYP1A2, a main pathway of olanzapine metabolism.
What to do
Monitor for sedation and orthostatic hypotension; no routine dose change is needed.
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 Olanzapine
Frequently asked questions
Can I take Cimetidine with Olanzapine?
MediHelp rates the interaction as minor. Cimetidine and Olanzapine 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 slightly increase olanzapine exposure. The clinical effect is usually small, though sedation or orthostasis could increase.
How serious is the interaction between Cimetidine and Olanzapine?
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 sedation and orthostatic hypotension; no routine dose change is needed.
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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