Selected Opioids/MAOIs Interactions

This information is generalized and not intended as specific medical advice. Consult your healthcare professional before taking or discontinuing any drug or commencing any course of treatment.

Medical warning:

Serious. These medicines may interact and cause very harmful effects. Contact your healthcare professional (e.g. doctor or pharmacist) for more information.

How the interaction occurs:

Both of these medicines can increase the level of serotonin in your body.

What might happen:

High serotonin levels may cause changes in body temperature, blood pressure, and behavior or mood, leading to a medical condition called Serotonin Syndrome. Serotonin Syndrome may be life threatening.

What you should do about this interaction:

Make sure your healthcare professional (e.g. doctor or pharmacist) knows that you are taking these medicines together.If you experience muscle twitching, tremors, shivering and stiffness, fever, heavy sweating, heart palpitations, restlessness, confusion, agitation, trouble with coordination, or severe diarrhea contact your doctor right away.Your healthcare professionals may already be aware of this interaction and may be monitoring you for it. Do not start, stop, or change the dosage of any medicine before checking with them first.

View Reference
  • 1.Boyer EW, Shannon M. The serotonin syndrome. N Engl J Med 2005 Mar 17; 352(11):1112-20.
  • 2.FDA (US Food and Drug Administration). FDA Drug Safety Communication: FDA warns about several safety issues with opioid pain medicines; requires label changes. available at: http://www.fda.gov/Drugs/DrugSafety/ucm489676.htm March 22, 2016.
  • 3.Rivers N, Horner B. Possible lethal reaction between Nardil and dextromethorphan. Can Med Assoc J 1970 Jul;103:85.
  • 4.Sovner R, Wolfe J. Interaction between dextromethorphan and monoamine oxidase inhibitor therapy with isocarboxazid. N Engl J Med 1988 Dec 22; 319(25):1671.
  • 5.Garbutt JC. Potentiation of propoxyphene by phenelzine. Am J Psychiatry 1987 Feb;144(2):251-2.
  • 6.Evans-Prosser CD. The use of pethidine and morphine in the presence of monoamine oxidase inhibitors. Br J Anaesth 1968 Apr;40(4):279-82.
  • 7.Carlsson A, Lindqvist M. Central and peripheral monoaminergic membrane-pump blockade by some addictive analgesics and antihistamines. J Pharm Pharmacol 1969 Jul;21(7):460-4.
  • 8.Avinza (morphine extended-release capsules) US prescribing information. Ligand Pharmaceuticals Incorporated April, 2014.
  • 9.Metharose (methadone hydrochloride) UK summary of product characteristics. Rosemone Pharmaceuticals Limited January 9, 2008.
  • 10.Darvon (propoxyphene hydrochloride) US prescribing information. Xanodyne Pharmaceuticals, Inc. September, 2009.
  • 11.Diskets Dispersible (methadone hydrochloride) US prescribing information. Cebert Pharmaceuticals, Inc. August, 2007.
  • 12.Ramsay RR, Dunford C, Gillman PK. Methylene blue and serotonin toxicity: inhibition of monoamine oxidase A (MAO A) confirms a theoretical prediction. Br J Pharmacol 2007 Nov;152(6):946-51.
  • 13.Peter C, Hongwan D, Kupfer A, Lauterburg BH. Pharmacokinetics and organ distribution of intravenous and oral methylene blue. Eur J Clin Pharmacol 2000 Jun;56(3):247-50.
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CONDITIONS OF USE: The information in this database is intended to supplement, not substitute for, the expertise and judgment of healthcare professionals. The information is not intended to cover all possible uses, directions, precautions, drug interactions or adverse effects, nor should it be construed to indicate that use of a particular drug is safe, appropriate or effective for you or anyone else. A healthcare professional should be consulted before taking any drug, changing any diet or commencing or discontinuing any course of treatment.