| Item |
Information |
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Drug Groups
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illicit; approved |
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Description
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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 |
| • |
Humans and other mammals |
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| 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 |
| • |
Coda BA, Rudy AC, Archer SM, Wermeling DP: Pharmacokinetics and bioavailability of single-dose intranasal hydromorphone hydrochloride in healthy volunteers. Anesth Analg. 2003 Jul;97(1):117-23, table of contents.
[Pubmed]
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