Methylthioninium chloride [methylene blue] injections have been associated with serotonin syndrome in SSRI recipients,

Methylthioninium chloride [methylene blue] injections have been associated with serotonin syndrome in SSRI recipients, according to a Health Canada "Notice to Hospitals". Several cases of serotonin syndrome resulting in admission to intensive care have been reported after patients have taken IV methylene blue in addition to SSRIs or drugs with similar properties. Health Canada advises caution when the drugs are administered together, saying that recipients of SSRIs should undergo a washout period equivalent to at least 4-5 half-lives before methylene blue administration. Prescribing information will be updated accordingly.

[Reference]

1. Health Canada.Association of serotonin toxicity with methylene blue injectable in combination with serotonin reuptake inhibitors. Internet Document: [2 pages], 16 Feb 2011. Available from: URL: http://www.hc-sc.gc.ca. .