Evaluation of Centrally Acting Cholinesterase Inhibitor Exposures in Adults

Background: There are 4 centrally acting cholinesterase inhibitors (CA-ChEI) available in the US: tacrine, galantamina, rivastigmine, and donepezil. Documented clinical experience involving exposure to these agents is limited. The lack of information makes decisions involving excessive or unintended CA-ChEI exposure difficult. Objective: TO assess the effects, demographics, and outcomes of CA-ChEI exposures reported to US poison centers. Methods: A retrospective review of the Toxic Exposure Surveillance System of the American Association of Poison Control Centers data of acute and acute-on-chrontc exposures involving only a CA-ChEI in patients 19 years of age or older with documented medical outcomes from 2000–2005 was performed. Results: There were 1026 records that met criteria for this study. Patients aged 70–89 years made up 73% of reports; 69% of the patients were female. Moderate (197) and major outcomes (20) accounted for 21% of exposures. There were no deaths. Clinical effects that occurred in 5% or more of patients included vomiting (34%), nausea (28%), diarrhea (12%), dizziness/vertigo (9.9%), drowsiness/lethargy (7.7%), diaphoresis (7.4%), tremor (5.2%), and bradycardia (5%). Patients were admitted to the hospital in 19% of all exposures. Of those patients, 42% were admitted to a critical care unit. The majority (65%) of exposures were attributed to unintentional therapeutic error. Patients received at least one form of therapy In 47% of exposures, including intravenous fluid (111), antiemetic (46), atropine (17), benzodiazepine (15), oxygen (14), antihypertensive (4), pralidoxime (4), intubation (3), antihistamine (2), antiarrhythmic (1), anticonvulsant (1), and pacemaker (1). Conclusions: The majority of patients evaluated in this retrospective study experienced no or mild effect; however, significant or life-threatening effects were observed in a small group of patients and an appreciable number of patients were admitted to a healthcare facility.

Evaluation of toxicity of topiramate exposures reported to poison centers

Published literature on the toxicity of a topiramate overdose is limited to case reports. This retrospective study of poison center data was performed to examine the severity of topiramate overdoses. Data on single substance exposures to topiramate reported to the American Association of Poison Control Centers (AAPCC) Toxic Exposure Surveillance System (TESS) in 2000 and 2001 were retrospectively analysed. A total of 567 cases met the inclusion criteria, of which 39% occurred in adults over 19 years of age and 30.2% in children 5 / 4 years old. The majority of patients (62.1%) experienced no toxicity. The most common clinical effects reported were drowsiness/lethargy (15.5%), dizziness/vertigo (4.9%), agitation (4.9%), confusion (3.9%), nausea (2.6%) and vomiting (2.5%). Symptomatic patients were older than asymptomatic patients and adults were more likely to be managed in a healthcare facility (P B / 0.0001). Patients who received gastrointestinal decontamination experienced less serious outcomes than those without decontamination (P B / 0.02). It is concluded that clinicians should expect relatively mild mental status changes in adults or children with toxicity from topiramate overdose. Serious toxic effects, such as CNS depression with respiratory depression or persistent non-anion gap metabolic acidosis, are infrequent.