Does Codeine Interact With Morphine?

Use of cytochrome P450 3A4 inducers, 3A4 inhibitors, or 2D6 inhibitors with Codeine Sulfate Tablets requires careful consideration of the effects on the parent drug, codeine, and the active metabolite, morphine.

Severity: Moderate

Severity basis: boxed warning (keywords: consider). Combining Codeine (Opioid analgesic) and Morphine (Opioid analgesic) is classified as a moderate interaction.

What to Do

Use this combination with caution. Your prescriber may monitor you more closely or adjust doses.

From the FDA Label

Use of cytochrome P450 3A4 inducers, 3A4 inhibitors, or 2D6 inhibitors with Codeine Sulfate Tablets requires careful consideration of the effects on the parent drug, codeine, and the active metabolite, morphine.

Source: FDA structured product labeling (set_id 010905f9-3bcb-4b50-9fe8-a3ad0010f14c).

Codeine

Opioid analgesic

Brands: Tylenol with Codeine

View Codeine safety profile

Morphine

Opioid analgesic

Brands: MS Contin, Kadian

View Morphine safety profile

Check these against your full medication list in our free Interaction Checker

This information is educational — not medical advice.

This page is provided for general educational purposes and summarizes publicly available data from sources such as the U.S. Food & Drug Administration. It is not a substitute for the judgment of a licensed clinician and should not be used to start, stop, or change any medication. It may be incomplete or out of date, and individual circumstances vary. Always talk with your prescriber or pharmacist about your specific medications and health conditions. If you think you may have a medical emergency, call 911.

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