FDA Says Zyvox, Methylene Blue Can Cause Potentially Fatal Reaction When Taken with Some Psych Meds

Taking certain psychiatric medications, including Zoloft, Pristiq, Cymbalta, Paxil and Wellbutrin, with the drugs <"http://www.yourlawyer.com/topics/overview/zyvox-serotonin-syndrome-ssri-antidepressants-side-effects-lawsuits">Zyvox or methylene blue – both of which are reversible monoamine oxidase inhibitors (MAOIs) – can induce a severe and potentially fatal central nervous system reaction called serotonin syndrome. According to a Drug Safety Communication issued yesterday by the U.S. Food & Drug Administration (FDA), the Adverse Event Reporting System database has received reports of these reactions in patients taking such drug combinations, including some fatalities associated with Zyvox.

Zyvox is an antibiotic used to treat drug-resistant bacteria including methicillin-related Staphylococcus aureus (MSRA), skin infections and nosocomial pneumonia. Methylene blue is used to treat methemoglobinemia, vasoplegic syndrome, ifosfamide-induced encephalopathy, and cyanide poisoning. It is also used as a dye in therapeutic and diagnostic applications.

According to the FDA, it is believed that when either Zyvox or methylene blue is given to patients taking serotonergic psychiatric medications, high levels of serotonin can build up in the brain, causing toxicity. Signs and symptoms of serotonin syndrome include mental changes (confusion, hyperactivity, memory problems), muscle twitching, excessive sweating, shivering or shaking, diarrhea, trouble with coordination, and/or fever.

Serotonergic psychiatric medications include selective serotonin reuptake inhibitor (SSRI) antidepressants, dual inhibitors of serotonin and norepinephrine reuptake, tricyclic and MAOI antidepressants, and atypical drugs such as Wellbutrin. Although the exact mechanism of this drug interaction is unknown, the FDA said methylene blue inhibits the action of monoamine oxidase A—an enzyme responsible for breaking down serotonin in the brain. It is also believed that Zyvox may act in the same way.

Because patients taking psychiatric medications may still need to receive either Zyvox or methylene blue when they present with serious conditions for which these drugs are the best treatment, the FDA has recommended that physicians should weigh the risks of using other treatments against the danger of serotonin syndrome.

In nonemergency situations where use of Zyvox or methylene blue is planned, antidepressant therapy should be stopped at least two weeks in advance. The one exception is Prozac, which should be stopped fives weeks prior because of its longer half-life.

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