Cimetidine and Morphine interaction

Cimetidine and Morphine: the Morphine prescribing label describes an interaction that usually calls for monitoring, a dose change, or spacing the doses.

Moderate

Usually manageable with monitoring or a dose change. Tell your pharmacist you take both.

What the FDA labels say

From the Morphine (Morphine Sulfate) label · effective 2026-02-03

Moderate

Intervention: Evaluate patients for increased respiratory and CNS depression when Morphine Sulfate Oral Solution is used concomitantly with cimetidine.

Drug interactionsnames CimetidineView label on DailyMed
Minor

Cimetidine Clinical Impact: The concomitant use of morphine and cimetidine has been reported to precipitate apnea, confusion, and muscle twitching in an isolated report.

Drug interactionsnames CimetidineView label on DailyMed

Taking more than these two? Interactions stack. Check your whole list at once; it stays in your browser.

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Not medical advice. Interaction Checker quotes FDA label text and NIH fact sheets. Whether an interaction matters for you depends on doses, timing, kidney and liver function, and other conditions. Confirm with a pharmacist or prescriber.