propanediol
n. any of a group of chemically related compounds derived from propyl alcohol and originally developed as antianxiety drugs. Their pharmacological actions include muscle relaxation, depression of the central nervous system, and a calming effect through interference with autonomic reactions. The prototype of the group is meprobamate. Due to their toxicity in overdose, propanediols have largely been supplanted as anxiolytics by benzodiazepines and other sedative-hypnotics; carisoprodol, a precursor of meprobamate, is currently used as a muscle relaxant.