Ann M Arens1,2, Krishna Shah3, Suad Al-Abri4, Kent R Olson4,5, Tom Kearney2. 1. a Department of Emergency Medicine , Hennepin County Medical Center , Minneapolis , MN , USA. 2. b Department of Emergency Medicine , University of California San Francisco , San Francisco , CA , USA. 3. c Department of Clinical Pharmacy , University of California San Francisco , San Francisco , CA , USA. 4. d Department of Emergency Medicine , Sultan Qaboos University Hospital , Muscat , Oman. 5. e Department of Medicine , University of California San Francisco , San Francisco , CA , USA.
Abstract
BACKGROUND: Physostigmine has long been recognized as an antidote to reverse anticholinergic delirium. However, its effectiveness, safety profile, and dosing have been disputed. OBJECTIVES: To describe effectiveness, adverse events, and dosing associated with the use of physostigmine to reverse anticholinergic delirium. METHODS: A retrospective cohort study of hospitalized patients reported to a regional poison center system between 2003 and 2012 who received physostigmine to reverse an anticholinergic toxidrome. Data extraction of a priori defined variables were recorded with concurrence of investigators. The cases were stratified by the primary ingestant as the presumed causative agent and associations for response were performed using odds ratios (ORs), 95% confidence intervals (CI's), and p values. RESULTS: Of the 1422 cases identified, 191 met the inclusion criteria. Patients exposed to non-diphenhydramine antihistamines (n = 14), antipsychotics (n = 4), and tricyclic antidepressants (n = 3) had 100% response to physostigmine, whereas anticholinergic plants (n = 46/67; 68.7%, OR: 0.70; CI: 0.36-1.35), diphenhydramine (n = 43/56; 64.2%, OR: 1.30; CI: 0.63-2.68), and combination products (n = 8/10; 80%, OR: 1.48; CI: 0.30-7.24) had partial response rates. Of the included patients, 142 (74.3%) were treated with physostigmine alone, and 16 (8.4%) of these patients were discharged directly from the emergency department (ED). DISCUSSION: Most patients, 182 (95.3%), had no documented adverse effects. Four patients (2.1%) experienced emesis, two experienced QTc prolongation (1.0%), and two experienced seizures (1.0%). There was a single fatality 6 h after physostigmine administration. Average initial total doses of physostigmine ranged from 1.0 to 1.75 mg. Most patients were admitted to the ICU (n = 110; 57.6%), however, 36 (18.8%) patients were discharged directly from the ED. CONCLUSIONS: In this retrospective cohort study, physostigmine administration to reverse anticholinergic delirium had a good safety profile, and often improved or resolved anticholinergic delirium when administered in doses less than 2 mg.
BACKGROUND:Physostigmine has long been recognized as an antidote to reverse anticholinergic delirium. However, its effectiveness, safety profile, and dosing have been disputed. OBJECTIVES: To describe effectiveness, adverse events, and dosing associated with the use of physostigmine to reverse anticholinergic delirium. METHODS: A retrospective cohort study of hospitalized patients reported to a regional poison center system between 2003 and 2012 who received physostigmine to reverse an anticholinergic toxidrome. Data extraction of a priori defined variables were recorded with concurrence of investigators. The cases were stratified by the primary ingestant as the presumed causative agent and associations for response were performed using odds ratios (ORs), 95% confidence intervals (CI's), and p values. RESULTS: Of the 1422 cases identified, 191 met the inclusion criteria. Patients exposed to non-diphenhydramine antihistamines (n = 14), antipsychotics (n = 4), and tricyclic antidepressants (n = 3) had 100% response to physostigmine, whereas anticholinergic plants (n = 46/67; 68.7%, OR: 0.70; CI: 0.36-1.35), diphenhydramine (n = 43/56; 64.2%, OR: 1.30; CI: 0.63-2.68), and combination products (n = 8/10; 80%, OR: 1.48; CI: 0.30-7.24) had partial response rates. Of the included patients, 142 (74.3%) were treated with physostigmine alone, and 16 (8.4%) of these patients were discharged directly from the emergency department (ED). DISCUSSION: Most patients, 182 (95.3%), had no documented adverse effects. Four patients (2.1%) experienced emesis, two experienced QTc prolongation (1.0%), and two experienced seizures (1.0%). There was a single fatality 6 h after physostigmine administration. Average initial total doses of physostigmine ranged from 1.0 to 1.75 mg. Most patients were admitted to the ICU (n = 110; 57.6%), however, 36 (18.8%) patients were discharged directly from the ED. CONCLUSIONS: In this retrospective cohort study, physostigmine administration to reverse anticholinergic delirium had a good safety profile, and often improved or resolved anticholinergic delirium when administered in doses less than 2 mg.