Methylnaltrexone and Naltrexone interaction

Methylnaltrexone and Naltrexone: the Methylnaltrexone prescribing label flag this combination with the strongest language, such as a contraindication, a boxed warning, or an instruction to avoid it.

Major

Do not combine without a prescriber's guidance. The label language below is the strongest FDA uses.

What the FDA labels say

From the Methylnaltrexone (Relistor) label · effective 2024-05-01

Major

• Other Opioid Antagonists : Potential for additive effect and increased risk of opioid withdrawal; avoid concomitant use.

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Major

Other Opioid Antagonists Avoid concomitant use of RELISTOR with other opioid antagonists because of the potential for additive effects of opioid receptor antagonism and increased risk of opioid withdrawal.

Drug interactionsby drug classView 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.