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Drug Interactions between methadone and Relistor

This report displays the potential drug interactions for the following 2 drugs:

  • methadone
  • Relistor (methylnaltrexone)

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Interactions between your drugs

No interactions were found between methadone and Relistor. This does not necessarily mean no interactions exist. Always consult your healthcare provider.


A total of 658 drugs are known to interact with methadone.


A total of 9 drugs are known to interact with Relistor.

Drug and food interactions


methadone food

Applies to: methadone

Grapefruit juice can increase the blood levels and effects of methadone. If you regularly consume grapefruits or grapefruit juice, you should be monitored for side effects and/or changes in methadone levels. Do not increase or decrease the amount of grapefruit products in your diet without first talking to your doctor. Orange juice is not expected to interact.

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methylnaltrexone food

Applies to: Relistor (methylnaltrexone)

Food may reduce the absorption of methylnaltrexone when taken orally, which may lead to lower blood levels of the medication and possibly reduced effectiveness. You should take oral preparations of methylnaltrexone on an empty stomach at least 30 minutes before your first meal of the day.

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Therapeutic duplication warnings

No warnings were found for your selected drugs.

Therapeutic duplication warnings are only returned when drugs within the same group exceed the recommended therapeutic duplication maximum.

Drug Interaction Classification

These classifications are only a guideline. The relevance of a particular drug interaction to a specific individual is difficult to determine. Always consult your healthcare provider before starting or stopping any medication.
Major Highly clinically significant. Avoid combinations; the risk of the interaction outweighs the benefit.
Moderate Moderately clinically significant. Usually avoid combinations; use it only under special circumstances.
Minor Minimally clinically significant. Minimize risk; assess risk and consider an alternative drug, take steps to circumvent the interaction risk and/or institute a monitoring plan.
Unknown No interaction information available.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.