Treatment of dextropropoxyphene poisoning

Dextropropoxyphene overdose. Epidemiology, clinical presentation and management

This paper comprehensively reviews the worldwide situation regarding acute overdosage of dextropropoxyphene (propoxyphene). The changing epidemiology of this type of poisoning over the last 20 years is described with discussion of concurrent trends and, in particular, the effects of different preventive measures adopted in various countries. The clinical pharmacology of dextropropoxyphene relevant to the clinical toxic effects resulting from acute overdosage is described, and the management is detailed. In particular, the importance of early diagnosis and treatment is stressed in view of the potentially lethal complications that may suddenly occur with this poisoning. Recommendations for the correct use of the specific narcotic antagonist, naloxone, are made, together with other intensive supportive measures. As dextropropoxyphene is frequently taken together with other toxic agents, the concomitant effects of alcohol and sedative drugs are described and the treatment of paracetamol (acetaminophen) in combination with dextropropoxyphene is emphasised. The most effective preventive measures for the future are suggested, but caution is advised regarding the prescription for 'at risk' patients of alternative analgesics, which may be no safer in overdosage.

Dextropropoxyphene overdosage. Pharmacological considerations and clinical management

Dextropropoxyphene is a widely prescribed synthetic opiate-like drug of uncertain analgesic efficacy which, in acute overdosage, manifests all the features of opiate toxicity. It is rapidly absorbed and, in association with other central nervous system depressants such as alcohol or benzodiazepine drugs, may be rapidly fatal. Seriously overdosed patients are comatose with respiratory depression, vomiting, seizures and circulatory collapse; small pupils are a useful diagnostic marker. The first priority is to establish the airway and treat convulsions, if present. All the features of overdosage are then rapidly and safely reversed by the specific opiate antagonist naloxone given intravenously. High tissue concentrations and slow elimination of dextropropoxyphene metabolites make continued and intensive monitoring after resuscitation essential because sudden unpredictable deterioration may occur for up to 24 hours. Other more slowly toxic co-ingestants such as paracetamol (acetaminophen) are often present and should be detected and treated as necessary. Dextropropoxyphene poisoning is now probably one of the most common causes of self-poisoning death because, although there is an effective antidote, subjects frequently succumb before treatment can be made available.

Fatal dextropropoxyphene poisoning in Northern Ireland. Review of 30 cases

Data from 30 fatal cases of dextropropoxphene poisoning occurring in Northern Ireland over three years have been studied. All the victims had ingested more than therapeutic amounts, and many had also taken alcohol or other drugs. Most of the deaths were probably suicides. Death occurred very rapidly suggesting that the narcotic effects of dextropropoxyphene predominated, and this may explain the scarcity of clinical reports, It is suggested that many doctors are unaware of the danger of dextropropoxyphene in overdosage and that the problem of dextropropoxyphene poisoning in the United Kingdom has not been fully appreciated. This supposition, if correct, highlights the absence of a satisfactory early-warning system for serious drug effects including death.

The use of propoxyphene napsylate in the treatment of heroin and methadone addiction

The use of methadone in the treatment of heroin addiction continues to be controversial. Propoxyphene napsylate (Darvon N(R)) is a possible alternative and a pilot study was conducted to test its acceptability, safety and clinical efficacy in treating long term, "multi-relapse" heroin addicts. Findings indicate that propoxyphene napsylate suppresses many of the symptoms associated with opioid withdrawal phenomena. It should be viewed as a very promising therapeutic tool to be used in conjunction with psychological counseling and socio-vocational rehabilitation in detoxification and maintenance therapy for heroin or methadone addiction.