Peridaxon
Peridaxon was a drug used to treat Irumodic syndrome, a degenerative neurological disorder which caused progressive deterioration of the synaptic pathways. Peridaxon was simply palliative, as there was no known cure for the syndrome. 

In an alternate timeline, Jean-Luc Picard had been prescribed peridaxon, something he mentioned to Data. who recognized the drug as not being a cure. ()

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de:Peridaxon
Drugs