Correlation between prescription of various dextropropoxyphene preparations and their involvement in fatal poisonings

Overdose of Dologesic with a Fatal Outcome: A Case Report

Dologesic is a commonly prescribed analgesic in accident and emergency department. Yet report of overdose with this drug is not common. We report a case in which the patient developed cardiac arrest within an hour of ingestion. Dextropropoxyphene, a component of the drug Dologesic, used to be a common cause of fatalities after drug overdose in the seventies. It is highly toxic in overdose and therefore caution should be exercised when prescribing this drug.

Propoxyphene and the risk of out-of-hospital death

PURPOSE

The opioid analgesic propoxyphene was withdrawn from the US market in 2010, motivated by concerns regarding fatality in overdose and adverse cardiac effects, including prolongation of the QT interval. These concerns were based on case reports, summary vital statistics, and surrogate endpoint studies.

METHODS

Using the linked Tennessee Medicaid database (1992-2007), we conducted a retrospective cohort study that compared risk of sudden cardiac, medication toxicity, and total out-of-hospital death for propoxyphene users with that for comparable nonusers of any prescribed opioid analgesic and users of hydrocodone, an opioid with similar indications. Cohort members had 1,873,500 propoxyphene prescriptions, 1,873,500 matched nonuser control periods, and 936,750 matched hydrocodone prescriptions.

RESULTS

Current propoxyphene users had no increased risk for sudden cardiac death (versus nonusers: hazard ratio [HR] = 1.00 [0.81-1.23]; versus current hydrocodone users: HR = 0.91 [0.68-1.21]) but did have increased risk for medication toxicity deaths (versus nonusers: HR = 1.85 [1.07-3.19], p = 0.027; versus current hydrocodone users: HR = 2.10 [0.87-5.10], p = 0.100). Because toxicity deaths were a small proportion of study deaths, total out-of-hospital mortality differed by less than 10% between the study groups and was not significantly elevated for propoxyphene (versus nonusers: HR = 1.09 [0.95-1.25]; versus current hydrocodone users: HR = 1.06 [0.87-1.29] ).

CONCLUSIONS

Our findings support the concern that propoxyphene has greater toxicity in overdose but do not provide evidence that it increases the risk of sudden cardiac death.

Co-proxamol and suicide: preventing the continuing toll of overdose deaths

Restricting means for suicide is a key element in suicide prevention strategies of all countries where these have been introduced. Preventing deaths from analgesic overdoses is highlighted in the National Suicide Prevention Strategy for England. The problem of self-poisoning with the prescription-only drug co-proxamol (dextropropoxyphene plus paracetamol) has received attention in several countries. We have conducted a review of the international literature related to possible strategies to tackle this problem. In England and Wales in 1997-1999, 18% of drug-related suicides involved co-proxamol; these constituted 5% of all suicides. Death usually results from the toxic effects of dextropropoxyphene on respiration or cardiac function. Death from co-proxamol overdose may occur rapidly, the lethal dose can be relatively low, and the effects are potentiated by alcohol and other CNS depressants. The majority of co-proxamol overdose deaths occur before hospital treatment can be received. The risk can extend to others in the household of the person for whom the drug is prescribed. While there is limited evidence that educational strategies have been effective in reducing deaths from co-proxamol poisoning, initiatives in Scandinavia, Australia and the UK to restrict availability of co-proxamol have produced promising results. Given the paucity of evidence for superior therapeutic efficacy of co-proxamol over other less toxic analgesics, there are good reasons to question whether it should continue to be prescribed.

Fatal intoxications in a Swedish forensic autopsy material during 1992-2002

Compilations of substances detected in fatal intoxications are important in order to observe changes in intoxication patterns, to monitor effects of preventive work and to discover new trends in drug usage. The aim of the present study was to describe the current pattern of substances detected in fatal intoxications in Sweden. Fatal intoxications investigated at the Department of Forensic Chemistry, Linköping, Sweden, during 1992-2002, were analysed. All suicides, uncertain cases and accidents where the cause of death were fatal intoxications (ICD-9: E950, E980 and E859) were included and substances detected in more than 50 fatal intoxications (in femoral blood) were listed. For each substance, a cut off value was set, above which concentrations were considered toxic. Fatal intoxications were detected by forensic-chemical analyses in 12% (6998/60,314) of the forensic autopsies during the study period. Among the suicides, an average of 3.8 substances were detected per case, the corresponding figure for uncertain cases and accidents were 3.5 and 4.1 substances, respectively. Ethanol was by far the most frequently detected substance, detected in 43% (3039) of the fatal intoxications, of which 32% (960) had toxic concentrations, followed by propoxyphene, detected in 27% (1863) of the fatal intoxications of which 74% (1370) had toxic concentrations. The number of cases where ethanol and propoxyphene were detected decreased during the study period. Moreover, other CNS-active drugs such as antidepressants, analgesics and anxiolytics were also frequently detected. The drugs with high proportions of cases with toxic concentrations detected were propoxyphene, amitriptyline, zolpidem, carisoprodol, alprazolam, thioridazine, methadone and ketobemidone. Selective serotonin reuptake inhibitors (SSRI) and tricyclic antidepressants (TCA) were detected in 12% (833) and 10% (665), respectively. A significantly (P <0.001) higher proportion of cases where TCA were detected had toxic concentrations when compared with cases where SSRI were detected (64% versus 31%).