A patient presented with somnolence after a reported ingestion of liquid clonazepam, ethanol, and extended-release potassium chloride. The authors reported a negative standard toxicology screen and a separately measured ethanol concentration. The paper leaves the clonazepam exposure unquantified.
The reported history included 50 mg of liquid clonazepam and an undisclosed amount of ethanol. The patient arrived about two hours after ingestion. Ethanol was measured at 90.8 mg/dL. The report gives no clonazepam-specific confirmation or concentration, and its description of the standard screen does not supply the assay details needed to interpret its sensitivity for that exposure. The negative screen therefore provides limited evidence about the reported clonazepam intake.
Initial potassium was 3.9 mmol/L, but abdominal imaging showed opacities in the stomach. Endoscopy retrieved 99 of the 100 reported potassium tablets after lavage recovered none. Those findings support retention of the solid potassium formulation. They supply no measurement of the liquid clonazepam dose or of its contribution to somnolence. The case also provides no comparison that separates the effects of ethanol, the reported clonazepam, and other clinical factors.
In a retrospective review, obtain the original laboratory report and identify the specimen, collection time, panel targets and reporting thresholds. Keep the measured ethanol value separate from the reported clonazepam dose. For another example of why the laboratory details matter, see this analysis of negative urine screen reporting.
Source: Pérez Tuñón JG and colleagues. Toxicology Reports. 2014, 1:209–213. doi:10.1016/j.toxrep.2014.04.002.