Ketamine is one of several clinically important drugs whose therapeutic efficacy is due in part to their ability to act upon ion channels prevalent in nearly all biological systems. In studying eukaryotic and prokaryotic organisms in vitro, we show that ketamine short-circuits the growth and spatial expansion of three microorganisms, Stachybotrys chartarum, Staphylococcus epidermidis and Borrelia burgdorferi, at doses efficient at reducing depression-like behaviors in mouse models of clinical depression. Although our findings do not reveal the mechanism(s) by which ketamine mediates its antifungal and antibacterial effects, we hypothesize that a function of L-glutamate signal transduction is associated with the ability of ketamine to limit pathogen expansion. In general, our findings illustrate the functional similarities between fungal, bacterial and human ion channels, and suggest that ketamine or its metabolites not only act in neurons, as previously thought, but also in microbial communities colonizing human body surfaces.
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**Comment**

Ketamine is used for starting and maintaining anesthesia and induces a trance-like state while providing pain relief, sedation, and memory loss.  It can cause confusion and hallucinations as it wears off.  Discovered in 1962 it was used in the Vietnam War due to its safety and is on the WHO’s list of essential medicines.

It’s also used as a recreational drug in raves and as a club drug.  Due to this, it’s a schedule III substance in the U.S.