Onset of symptoms after methadone overdose

• Published in: The American journal of emergency medicine 2007, Vol.25 (1), p.57-59
• Main Authors: LoVecchio, Frank, DO, MPH, Pizon, Anthony, MD, Riley, Brad, MD, Sami, Azadeh, D'Incognito, Carmella
• Format: Article
• Language: English
• Subjects: Adolescent; Adult; Analgesics; Anesthesia. Intensive care medicine. Transfusions. Cell therapy and gene therapy; Biological and medical sciences; Clinical death. Palliative care. Organ gift and preservation; Confidence intervals; Data collection; Drug intoxications. Doping; Drug Overdose - drug therapy; Drug Overdose - physiopathology; Emergency; Emergency medical care; Humans; Ingestion; Intensive care medicine; Medical Records; Medical sciences; Methadone - poisoning; Middle Aged; Mortality; Naloxone - therapeutic use; Narcotic Antagonists - therapeutic use; Narcotics - poisoning; Overdose; Pharmacology. Drug treatments; Poison Control Centers; Retrospective Studies; Time Factors; Toxicity
• ISSN: 0735-6757; 1532-8171
• DOI: 10.1016/j.ajem.2006.07.006

Abstract Background Methadone ingestion may cause delayed coma and require naloxone infusion. Few studies exist regarding the time development of symptoms following methadone overdose in adults. Methods After a brief training period, reviewers who were blinded to the purpose of the study completed a standardized data collection sheet. Two consecutive years of poison center patient encounters were reviewed. Age, outcomes, coingestions, vital signs, clinical manifestations, hospital admissions, and mortality were abstracted. Data were analyzed using descriptive statistics. The first reviewer was designated to extract the data. The second reviewer conducted a review of 20% of all the charts for a κ value to be calculated. Results In total, 44 cases of isolated methadone overdose in patients older than 18 years were identified. A mean age of 32.5 (18-58) years and a mean presumed ingestion of 106 mg of methadone was calculated. Of the 44 patients, 32 received naloxone for symptoms consistent with opiate toxicity. All symptoms occurred within 9 hours of methadone ingestion, with a mean symptom onset of 3.2 hours. All patients had resolution of symptoms within 24 hours. No deaths were recorded. The κ score for interreviewer reliability was 0.69, with a 95% confidence interval of 0.58 to 0.73. Limitations This was a retrospective study that was limited by patient history. Conclusion Acute methadone toxicity typically results in symptoms within 9 hours of ingestion.