The following is a list of the most common drug interactions for methadone. This is by no means a complete list. Consult a physician or pharmacist for a complete list. Always inform your physician or pharmacist about the complete list of your medications so that you could be alerted to any dangerous interactions.
Concurrent use of methadone and such medications can increase the risk of respiratory depression, hypotension, and profound sedation , coma and death. Of particular concern among these drugs are the benzodiazepines. Deaths have been reported when methadone has been taken in conjunction with benzodiazepines. Closer monitoring is needed if these medications are used/abuses along with methadone. There are many drugs within the class of benzodiazepines but the mostly commonly used ones are: diazepam (Valium), lorazepam (Ativan), clonazepam (Klonipin), alprazolam (Xanax), oxazepam (Serax), temazepam (Restoril), chlordiazepoxide (Librium), etc.
Potentially Arrhythmogenic Agents:
Closer monitoring is needed for patients taking higher doses of methadone along with any drugs known to have the potential to prolong the QT interval. Consult your physician or pharmacist about these.
Opioid Antagonists, Mixed Agonist/Antagonists, and Partial Agonists:
Withdrawal symptoms, sometimes severe and prolonged, can be induced when someone on methadone is given opioid antagonists or mixed agonist/antagonists. Examples of pure antagonists are naloxone (Narcan), naltrexone (Revia or Vivitrol); and examples of mixed or partial agonists are pentazocine (Talwin) and buprenorphine (Suboxone or Subutex).