Psych · Emergency psychiatry
Overdose and toxicology for psychiatrists
Also known as Deliberate self-poisoning · Psychotropic overdose · Toxicology for psychiatry · Self-poisoning assessment · Toxidrome approach psychiatry
Fellowship hub on overdose and toxicology for psychiatrists: the found-down approach, relative lethal toxicity of psychotropics, TCA alkalinisation, serotonin toxicity criteria, paracetamol and acetylcysteine, decontamination limits, lithium and EXTRIP, naloxone and flumazenil. FRANZCP-primary, globally tagged.
Checked against its sources on 23 Oct 2026
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Red flags
- Tricyclic antidepressants had the highest relative fatal toxicity of all antidepressants in 16 years of Hunter Area data
- Unless a patient has an intact or protected airway, the administration of activated charcoal is contraindicated
- Activated charcoal does not bind lithium
- A patient who responds to naloxone should be kept under continued surveillance, since some opioids act longer than naloxone
Meet the patient
A 34-year-old woman is brought in "found down" at home, drowsy, surrounded by empty blister packs of amitriptyline, paracetamol and her mother's lithium. No one can time the ingestion. The ED registrar pages you for "psych clearance."
Why the examiner cares. Poisonings account for up to 10% of admissions to intensive care units; most patients recover with supportive care alone, but a significant proportion need targeted interventions and organ support.[18] About 30% of poison exposures reported to poison centres are referred to or begin within a health care facility.[16]
References17ShowHide
- [1]Chyka PA, Seger D, Krenzelok EP, Vale JA Position paper: Single-dose activated charcoal. Clin Toxicol (Phila), 2005.PMID 15822758
- [2]Thanacoody R, Caravati EM, Troutman B, et al. Position paper update: Whole bowel irrigation for gastrointestinal decontamination of overdose patients. Clin Toxicol (Phila), 2015.PMID 25511637
- [3]Whyte IM, Dawson AH, Buckley NA Relative toxicity of venlafaxine and selective serotonin reuptake inhibitors in overdose compared to tricyclic antidepressants. QJM, 2003.PMID 12702786
- [4]Isbister GK, Bowe SJ, Dawson A, et al. Relative toxicity of selective serotonin reuptake inhibitors (SSRIs) in overdose. J Toxicol Clin Toxicol, 2004.PMID 15362595
- [6]Pai K, Buckley NA, Isoardi KZ, et al. Optimising alkalinisation and its effect on QRS narrowing in tricyclic antidepressant poisoning. Br J Clin Pharmacol, 2022.PMID 34312917
- [7]Decker BS, Goldfarb DS, Dargan PI, et al. Extracorporeal Treatment for Lithium Poisoning: Systematic Review and Recommendations from the EXTRIP Workgroup. Clin J Am Soc Nephrol, 2015.PMID 25583292
- [8]Baird-Gunning J, Lea-Henry T, Hoegberg LCG, et al. Lithium Poisoning. J Intensive Care Med, 2017.PMID 27516079
- [9]Dunkley EJ, Isbister GK, Sibbritt D, et al. The Hunter Serotonin Toxicity Criteria: simple and accurate diagnostic decision rules for serotonin toxicity. QJM, 2003.PMID 12925718
- [11]Bateman DN, Dart RC, Dear JW, et al. Fifty years of paracetamol (acetaminophen) poisoning: the development of risk assessment and treatment 1973-2023 with particular focus on contributions published from Edinburgh and Denver. Clin Toxicol (Phila), 2023.PMID 38197864
- [12]Smilkstein MJ, Knapp GL, Kulig KW, Rumack BH Efficacy of oral N-acetylcysteine in the treatment of acetaminophen overdose. Analysis of the national multicenter study (1976 to 1985). N Engl J Med, 1988.PMID 3059186
- [13]Williams K, Lang ES, Panchal AR, et al. Evidence-Based Guidelines for EMS Administration of Naloxone. Prehosp Emerg Care, 2019.PMID 30924736
- [14]Walley AY, Xuan Z, Hackman HH, et al. Opioid overdose rates and implementation of overdose education and nasal naloxone distribution in Massachusetts: interrupted time series analysis. BMJ, 2013.PMID 23372174
- [15]Veiraiah A, Dyas J, Cooper G, et al. Flumazenil use in benzodiazepine overdose in the UK: a retrospective survey of NPIS data. Emerg Med J, 2012.PMID 21785147
- [16]Parris MA, Calello DP Found Down: Approach to the Patient with an Unknown Poisoning. Emerg Med Clin North Am, 2022.PMID 35461619
- [17]Brett J, Wylie CE, Raubenheimer J, Isbister GK, et al. The relative lethal toxicity of pharmaceutical and illicit substances: A 16-year study of the Greater Newcastle Hunter Area, Australia. Br J Clin Pharmacol, 2019.PMID 31173392
- [18]Hüser C, Bethlehem C, Dünser MW, et al. Critical care management of the patient with pharmaceutical poisoning. Intensive Care Med, 2025.PMID 41222651
- [19]US National Library of Medicine DailyMed NALOXONE HYDROCHLORIDE INJECTION [DR. REDDY'S LABORATORIES, INC.] DailyMed, 2026.Source