Benzonatate Ingestion Reported to the National Poison Center Database System (NPDS)

Abstract

Little has been published on benzonatate ingestion, with the few case reports suggesting significant risk of seizures after poisoning. A 7-year retrospective review of all single substance ingestion of benzonatate reported to the National Poison Center Database System (NPDS) from 2000 to 2006. In this review, there were 2,172 patients, of which 1,280 (58%) were female. Mean age was 20years, with 676 (30%) <6years. Serious outcomes occurred in 116 (moderate, n = 81, 4%; major, n = 31, 1%; and death, n = 4, 0.2%). Mean age of those with serious outcome was 21years, with 41 (35%) in children less than 6years old. Forty-nine percent (1,084) patients were treated in a healthcare facility (HCF) of which 148 (7%) were admitted for medical care. Clinically significant effects that were documented included tachycardia (n = 31, 1%), agitation (n = 30, 1%), seizure (n = 23, 1%), coma (n = 14, 0.6%), ventricular dysrhythmia (n = 9, 0.4%), cardiac arrest (n = 8, 0.3%), hypotension (n = 7, 0.3%), and asystole (n = 6, 0.2%). Of patients with seizures reported, eight patients (0.4%) had multiple/discrete seizures and two had status epilepticus documented. Dysrhythmias but not seizures occurred in all fatalities in this review. Significant CNS and cardiac effects occurred in a small subset of this study (<1%), while half the patients received direct medical care in an HCF. No correlation between age and severity of medical outcome was detected by statistical analysis. A prospective study to better evaluate potential HCF triage criteria such as dosage, age, or preexisting conditions may be warranted. The fatalities from this study were due to dysrhythmias rather than seizures as previously reported in previous case reports. There were no clinical correlations between severity of outcomes and dose ingested. A median dose of 200mg or greater suggests a potential for producing serious outcomes in a benzonatate exposure.