Serious CNS Reactions Possible in Patients Taking MAOI Drugs, Says FDA

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On Tuesday, the Food and Drug Administration (FDA) released two drug-safety communications regarding serious CNS reactions that are possible when a patient is taking serotonin psychiatric medications. Both the antibacterial drug Zyvox (linezolid) and the drug methylene blue inhibit the action of monoamine oxidase A, an enzyme responsible for breaking down serotonin in the brain. Either drug may lead to serotonin build-up in the brain, causing the toxicity known as serotonin syndrome. Symptoms include mental changes (confusion, hyperactivity, memory problems), muscle twitching, excessive sweating, shivering, diarrhea, trouble with coordination, and/or fever.

Linezolid is used to treat pneumonia, infections of the skin, and infections caused by a resistant bacterium (Enterococcus faecium). Methylene blue is used to treat methemoglobinemia, vasoplegic syndrome, ifosfamide-induced encephalopathy, and cyanide poisoning. It is also used as a dye in diagnostic applications. The FDA recommends these two drugs not be given to patients taking serotonergic drugs, but recognizes there are some conditions that may be life-threatening or require urgent treatment with those drugs. 

Timely news about psychiatric drugs can be found regularly in the "Med Check" column of Psychiatric News. See the latest at http://pn.psychiatryonline.org/content/46/12/18.2.full.