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FDA: Linezolid and Methylene Blue Can Interact with Serotonergic Drugs, Cause CNS Reactions

Linezolid and methylene blue can cause potentially fatal central nervous system (CNS) reactions when given to patients who are taking serotonergic psychiatric medications, the FDA warned last week.

Linezolid is an antibiotic, and methylene blue is used in diagnostic procedures and to treat various conditions, such as methemoglobinemia and cyanide poisoning.

Both drugs inhibit monoamine oxidase A, an enzyme that breaks down serotonin in the brain. Accordingly, their use in patients taking serotonergics could lead to lethal levels of serotonin.

The FDA said that while linezolid and methylene blue generally should not be used in patients on serotonergics, they may be necessary in urgent situations. In such cases, the serotonergic should be stopped immediately and not resumed until 24 hours after the last dose of linezolid or methylene blue. Patients should be closely monitored for serotonin syndrome and related CNS reactions, and should be educated about the signs and symptoms of reactions (e.g., confusion, hyperactivity, memory problems, muscle twitching, excessive sweating).

LINK(S):

FDA MedWatch alert on linezolid (Free)

FDA MedWatch alert on methylene blue (Free)

Published in Physician's First Watch August 1, 2011

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