Molecule

Drug Groups

illicit; approved

Description

A narcotic analgesic structurally related to methadone. Only the dextro-isomer has an analgesic effect; the levo-isomer appears to exert an antitussive effect. [PubChem]

Indication

For the relief of mild to moderate pain

Pharmacology

Propoxyphene, a synthetic opiate agonist, is structurally similar to methadone. Its general pharmacologic properties are those of the opiates as a group. The analgesic effect of propoxyphene is due to the d-isomer, dextropropoxyphene. It binds to the opiate receptors and leads to a decrease of the perception of pain stimuli. Propoxyphene possesses little to no antitussive activity and no antipyretic action.

Toxicity

Coma, respiratory depression, circulatory collapse, and pulmonary edema. Seizures occur more frequently in patients with propoxyphene intoxication than in those with opiate intoxication. LD₅₀=230mg/kg (orally in rat, Emerson)

Affected Organisms

Biotransformation

Hepatic

Half Life

6-12 hours

Elimination

The major route of metabolism is cytochrome CYP3A4 mediated N-demethylation to norpropoxyphene, which is excreted by the kidneys.
In 48 hours, approximately 20% to 25% of the administered dose of propoxyphene is excreted via the urine, most of which is free or conjugated norpropoxyphene.

Distribution

* 16 L/kg

Clearance

* 2.6 L/min

References

External Links