Other safety alerts
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| The United States: Methylene Blue: Drug Safety Communication - serious CNS reactions possible when given to patients taking certain psychiatric medications |
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FDA has received reports of serious central nervous system (CNS) reactions when the drug methylene blue is given to patients taking psychiatric medications that work through the serotonin system of the brain (serotonergic psychiatric medications). A list of the serotonergic psychiatric medications that can interact with methylene blue can be found in the Drug Safety Communication. Methylene blue is used to treat methemoglobinemia, vasoplegic syndrome, ifosfamide-induced encephalopathy, and cyanide poisoning. Methylene blue is a potent, reversible monoamine oxidase inhibitor (MAOI). Although the exact mechanism of this drug interaction is unknown, methylene blue inhibits the action of monoamine oxidase A — an enzyme responsible for breaking down serotonin in the brain. It is believed that when methylene blue is given to patients taking serotonergic psychiatric medications, high levels of serotonin can build up in the brain, causing toxicity. This is referred to as Serotonin Syndrome — signs and symptoms include mental changes (confusion, hyperactivity, memory problems), muscle twitching, excessive sweating, shivering or shaking, diarrhea, trouble with coordination and/or fever. Safety information about this potential drug interaction and important drug usage recommendations for emergency and non-emergency situations are being added to the drug labels for serotonergic psychiatric medications.
Please refer to the following website in FDA for details:
http://www.fda.gov/Safety/MedWatch/SafetyInformation/SafetyAlertsforHumanMedicalProducts/ucm265476.htm
In Hong Kong, Methylene Blue Inj (HK-59020) is registered by Sino-Asia Pharmaceutical Supplies Ltd. It is used in the treatment of methemoglobinemia. The news on the drug interaction with serotonin reuptake inhibitors has been released by Health Canada and was posted on the website of Pharmaceutical Service on 18 February 2011. A letter to inform healthcare professionals was issued on the same day and press release was issued on 21 February 2011. In view of FDA's recommendation, a letter to inform healthcare professionals will be issued and the matter will be discussed in the coming meeting of the Registration Committee of the Pharmacy and Poisons Board.
Ends/ Wednesday, July 27, 2011
Issued at HKT 12:30
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