Outcomes of unintentional beta-blocker or calcium channel blocker overdoses: a retrospective review of poison center data.

Outcomes following unintentional, supratherapeutic ingestions of a patient's own beta-blocker (BB) or calcium channel blocker (CCB) have not been well studied. A retrospective review of all poison control center (PCC) charts from January 2007 through December 2009 yielded 4,099 cases involving a BB or CCB. Of these, 436 (10.6%) met inclusion criteria. Data abstracted included patient age/gender, medication(s) involved, dose(s), time interval between ingestions, symptoms, and outcome. Exclusion criteria included intentional ingestions, ingesting someone else's medication, and ingestion intervals >12 h. Outcomes were defined as the development of symptoms, management site, hospital admission, and death. Mean age was 65.1 years (range 2-91; SD 17.9); 284 (65.1%) were women. Eighty-two (18.8%) cases resulted in ED evaluation; 44 (53.7%) of these were referred in by the PCC. Symptoms developed in 44 (10.1%) cases and 32 (7.3%) were admitted due to the ingestion. Of those admitted, five (15.6%) received treatment (three intravenous fluids, one glucagon, one calcium). Of the 343 (78.7%) cases initially observed on site, three (0.9%) were later referred to an ED; none required treatment. There was one death under extenuating circumstances. The validity of data abstraction was determined for six variable using 43 charts [0.97; 95% CI (0.91-0.99)]. Based on a retrospective analysis of PCC cases, home observation of asymptomatic patients following unintentional supratherapeutic ingestions of their own BB or CCB was safe in most cases. Further, prospective study is required to identify risks factors for becoming symptomatic or requiring treatment.