Talacen

Pentazocine is a synthetically-prepared narcotic (opioid analgesic) drug used to treat mild to moderately severe pain. Pentazocine is sold under several brand names, such as Talwin (with naloxone) and Talacen (with acetaminophen). It should be noted that this compound may exist as one of two enantiomers, named (+)-pentazocine and (-)-pentazocine. (-)-pentazocine is a kappa-opioid receptor agonist, while (+)-pentazocine is not, and displays selectivity to the related sigma receptor.
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Pentazocine /pen·taz·o·cine/ a synthetic opioid analgesic, used in the form of the hydrochloride and lactate salts as an analgesic and anesthesia [more]Talacen - Community and Resources