Propoxyphene, (+/-)-

**Semantic type:** Pharmacologic Substance

**Definition:** A racemic mixture of propoxyphene, a synthetic opiate agonist with narcotic analgesic activity. The analgesic effect of propoxyphene is due to its d-isomer, dextropropoxyphene, which bind to opiate receptors, primarily the OP3 receptor located within the central nervous system (CNS). Mediated through G-protein coupled OP3 receptors and cAMP signaling, the release of nociceptive neurotransmitters such as substance P, gamma-aminobutyric acid (GABA), dopamine, acetylcholine, and noradrenaline is inhibited. Propoxyphene also inhibits the release of vasopressin, somatostatin, insulin and glucagon and close N-type voltage-operated calcium channels and open calcium-dependent inwardly rectifying potassium channels. This results in hyperpolarization and reduced neuronal excitability.

**Synonyms:** - DL-Propoxyphene - PROPOXYPHENE, (+/-)-