Drug interactions
Cimetidine + Opium tincture
Severity: Moderate
Cimetidine and Opium tincture: 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 inhibits hepatic metabolism and may raise exposure to morphine, the main opium alkaloid. Increased sedation and respiratory depression are possible but morphine is mostly glucuronidated, so the effect is modest.
What this interaction means in plain words
Cimetidine and Opium tincture 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.
Why it happens
Cimetidine inhibition of hepatic CYP enzymes may reduce opioid alkaloid clearance.
What to do
Monitor for sedation and respiratory depression, and lower the opium tincture dose if needed. Consider famotidine as an alternative.
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
Frequently asked questions
Can I take Cimetidine with Opium tincture?
MediHelp rates the interaction as moderate. Cimetidine and Opium tincture 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 inhibits hepatic metabolism and may raise exposure to morphine, the main opium alkaloid. Increased sedation and respiratory depression are possible but morphine is mostly glucuronidated, so the effect is modest.
How serious is the interaction between Cimetidine and Opium tincture?
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 sedation and respiratory depression, and lower the opium tincture dose if needed. Consider famotidine as an alternative.
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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