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Drug
Information
Pharmacokinetics
| Indication
& Dosage | Action
| Interactions
Adverse
Effect & Precautions |
Brands available in Market
Pharmacokinetics
Dextropropoxyphene is readily absorbed from the gastrointestinal tract, the napsylate tending to be more slowly absorbed than the hydrochloride, but both are subject to considerable first-pass metabolism. Peak plasma concentrations occur about 1 to 2 hours after ingestion. It is rapidly distributed and concentrated in the liver, lungs, and brain. About 80% of dextropropoxyphene and its metabolites are reported to be bound to plasma proteins. Dextropropoxyphene crosses the placenta. It has been detected in breast milk but some authorities consider that the amount is too small to be harmful to a breast-fed infant.
Dextropropoxyphene is N-demethylated to nordextropropoxyphene (norpropoxyphene), in the liver. It is excreted in the urine mainly as metabolites. It is now recognised that dextropropoxyphene and nordextropropoxyphene have prolonged elimination half-lives; values of 6 to 12 hours and 30 to 36 hours, respectively, have been reported. Accumulation of dextropropoxyphene and its metabolites may occur with repeated doses and nordextropropoxyphene may contribute to the toxicity seen with overdosage.
Oral
Acute exacerbations of rheumatoid arthritis or osteoarthritis, spondylitis, various musculoskeletal conditions with pain: As Hcl 65mg 3-4 times daily usually in conbination with other drugs,
Children : Not recommended usually.
A relatively week opioid analgesic. Has no antitussive effect. Usually given in combination with NSAIDs or other analgesics
Barbiturate anaeshetics: May increase respiratory and CNS depressive effects of propoxyphene.
Warfarin: Potentiation of hypoprothrombinemic effect.
Carbamazepine: May increase serum carbamazepine levels with resultant toxicity.
Adverse
Effect & Precaution
Nausea, Vomiting, epigastric distress and sedation.
Precaution: Additive CNS effects with sedatives. Hypnotics, Barbiturates
and alcohol. Driving and operating machinery.
Pregnancy: Contraindicated.
Breast Feeding: Use with caution.
Man: May be given in reduced dose.
