EMedHome's Clinical Pearl
Starting to think there's nothing ketamine can't do? That's understandable considering that the recent literature indicates another role for ketamine—this time to treat benzodiazepine-resistant severe alcohol withdrawal. Ketamine offers a logical mechanism to treat severe alcohol withdrawal: High doses of ethanol competitively antagonize NMDA receptors, and the unopposed NMDA receptors lead to excitatory symptoms during withdrawal.
Ketamine is an NMDA receptor antagonist, and it treats ethanol withdrawal at a receptor not addressed by traditional therapy. Ketamine also has a low potential for respiratory depression. A just-released retrospective observational study of 63 patients found that a ketamine infusion in patients with delirium tremens was associated with reduced GABA-agonist (benzodiazepines and phenobarbital) requirements, shorter ICU length of stay, and fewer intubations. (Crit Care Med 2018 May 8. doi: 10.1097/CCM.0000000000003204.) Ketamine was infused at 0.15-0.3 mg/kg/hr until delirium resolved as an adjunct to standard symptom-triggered GABA agonist dosing.
Another just-released review included 30 patients receiving ketamine adjunctively with a lorazepam infusion for severe alcohol withdrawal. (J Med Toxicol 2018 May 10. doi: 10.1007/s13181-018-0662-8.) Mean time to initiation of ketamine after the initiation of a lorazepam infusion was 41 hours. All patients achieved initial symptom control within one hour of ketamine initiation. Median initial ketamine infusion rate was 0.75 mg/kg/hr.
A 2015 study also evaluated patients receiving an infusion of 0.20 mg/kg/hr of ketamine IV. (Drug Alcohol Depend 2015;154:296.) Ketamine reduced the amount of benzodiazepine required. Ketamine is readily available in the ED, and EPs are familiar with its use. Currently, phenobarbital and propofol have more literature support than ketamine in benzodiazepine-resistant withdrawal, but this is changing, and ketamine is an option as an adjunctive medication. (Am J Emerg Med 2017;35:1005.)
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Amal Mattu, MD, and Colleagues: STEMI Mimics You Can't Afford to Miss: http://bit.ly/MattuEMN. Dr. Mattu is one of the premier speakers in emergency medicine, and a professor of emergency medicine and the vice chair of emergency medicine at the University of Maryland School of Medicine in Baltimore.
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Rob Rogers, MD: Don't Let Your Next MI Patient Be You: http://bit.ly/EMN-EMedHomeVideos. Dr. Rogers is an associate professor and the director of medical education and the teaching fellowship in emergency medicine at the University of Maryland School of Medicine.