Disposition of propoxyphene and norpropoxyphene in man after a single oral dose

Abstract

Department of Pharmacology, Cornell University Medical CollegeThe disposition of propoxyphene in man has been only reeently explored beeause earlier methods were either nonspecifie or laeked the sensitivity required to quantitate the sm all amounts of this drug present in human plasma. In 1968, Wolen and Gruber l l developed a gas-liquid chromatographie ( GLC ) method for the quantitative determination of propoxyphene in plasma. They found that 3 subjeets who had reeeived the same dose differed widely in plasma propoxyphene levels. This' variation was unrelated to the body weight of the subjects. MeMahon and associates" studied propoxyphene disposition in man with 14C-Iabeled drug. They found that N-demethylation was an important biotransformation pathway for propoxyphene, and in man norpropoxyphene was the most important biotransformation produet. 302In order to determine more precisely the degree of individual variation in the disposition of propoxyphene, a GLC method was developed that permits the simultaneous quantitation of both propoxyphene

ECG Abnormalities in Co-proxamol (Paracetamol/Dextropropoxyphene) Poisoning

“…We have assumed that both paracetamol and dextropropoxyphene have a similarly rapid absorption rate. Previous reports suggest dextropropoxyphene is rapidly absorbed from the gastrointestinal tract and detectable in plasma 5 min after administration of the napthylate and hydrochloride by mouth (19), the peak concentration in plasma is reached between 1 and 2 h after oral administration to an empty stomach (20). Long plasma half-lives of dextropropoxyphene and norpropoxyphene have been reported in overdose (21), following repeated doses (22) and in the elderly (23).…”

An Unusual Presentation of Spasmoproxyvon Dependence from Manipur, India

“…Due to prolonged halflife, norpropoxyphene is believed to play a role in the prolonged clinical course following an overdose. [8][9][10] Normally the therapeutic concentration for dextropropoxyphene is about 0.4 mg/L, and plasma concentration in serious toxicity is found to be over 1 mg/L. 11 Convulsions and delirium are the major effects of overdose.…”

Pharmacokinetics of Propoxyphene

“…The peak concentration in plasma is reached at between 1 and 2 h after oral administration on an empty stomach (Verebely & Inturrisi, 1974). The absorption of the drug was delayed by standard highcarbohydrate, high-fat and high-protein meals but the overall efficiency of absorption was unaffected or slightly increased.…”

“…The plasma level of norpropoxyphene reaches a higher and later peak concentration than the parent drug (Verebely & Inturrisi, 1974). The half-life of norpropoxyphene is longer than that of propoxyphene and has been variously reported as 6.1 (Inturrisi et al, 1982), 16.8 (Verebely & Inturrisi, 1974) and 22.9 h (Gram et al, 1979).…”