Contributor: Aaron Lessen MD Educational Pearls: What is Carbamazepine (Tegretol)? Carbamazepine is an anti-epileptic drug with mood-stabilizing properties that is used to treat bipolar disorder, epilepsy, and neuropathic pain. It functions primarily by blocking sodium channels which can prevent repetitive action potential firing. What are the symptoms of an overdose? Common initial signs include diminished conscious state, nystagmus, ataxia, hyperreflexia, CNS depression, dystonia, and tachycardia Severe toxicity can cause seizures, respiratory depression, decreased myocardial contractility, pulmonary edema, hypotension, and dysrhythmias. How is an overdose treated? An overdose is treated with large doses of activated charcoal and correction of electrolyte disturbances. Be ready to intubate given the potential for respiratory depression. Carbamazepine is moderately dialyzable and dialysis is recommended in severe overdoses. Additional educational pearl: Individuals in correctional facilities can occasionally self-administer medications which means that medication overdose should still be on the differential for any of these individuals. References Epilepsies in children, Young People and adults: NICE guideline [NG217]. National Institute for Health and Care Excellence. (2022, April 27). https://www.nice.org.uk/guidance/ng217  Ghannoum M, Yates C, Galvao TF, Sowinski KM, Vo TH, Coogan A, Gosselin S, Lavergne V, Nolin TD, Hoffman RS; EXTRIP workgroup. Extracorporeal treatment for carbamazepine poisoning: systematic review and recommendations from the EXTRIP workgroup. Clin Toxicol (Phila). 2014 Dec;52(10):993-1004. doi: 10.3109/15563650.2014.973572. Epub 2014 Oct 30. PMID: 25355482; PMCID: PMC4782683. Seymour JF. Carbamazepine overdose. Features of 33 cases. Drug Saf. 1993 Jan;8(1):81-8. doi: 10.2165/00002018-199308010-00010. PMID: 8471190. Spiller HA. Management of carbamazepine overdose. Pediatr Emerg Care. 2001 Dec;17(6):452-6. doi: 10.1097/00006565-200112000-00015. PMID: 11753195. Tran NT, Pralong D, Secrétan AD, Renaud A, Mary G, Nicholas A, Mouton E, Rubio C, Dubost C, Meach F, Bréchet-Bachmann AC, Wolff H. Access to treatment in prison: an inventory of medication preparation and distribution approaches. F1000Res. 2020 May 13;9:357. doi: 10.12688/f1000research.23640.3. PMID: 33123347; PMCID: PMC7570324. Summarized by Jeffrey Olson, MS2 | Edited by Meg Joyce & Jorge Chalit, OMSII