Emergency room use of opioid antagonists in drug intoxication and overdose
Opioid receptor antagonists are effective at reversing the clinical features of opioid toxicity; however, if administered overenthusiastically, they can precipitate acute withdrawal symptoms (AWS) in regular opioid users. These symptoms may cause the patients to discharge themselves against medical advice and they are in danger of renarcotization either due to the effect of the antagonists wearing off or because of the patients seek further opioids, often in larger doses, to overcome AWS. Clinicians treating opioid overdose are therefore walking a clinical tightrope between undertreating the patient and precipitating AWS. The three opioid antagonists that have been licensed for clinical use are naloxone, naltrexone, and nalmefene. Unfortunately, the latter two have long durations of action which may cause prolonged AWS, and they are not recommended for Emergency Department treatment of acute opioid toxicity. The evidence base for the appropri ate dose, route of administration, and observation of opioid-intoxicated patients is presented, and a clinical algorithm has been developed. Optimal therapy includes careful titration of intravenous boluses of naloxone so that patients are able to main tain their own airway and breathe adequately, without precipitating AWS, followed by at least 2-h observation. The subcutaneous and intramuscular routes should only be used if intravenous access cannot be established.