Site dependence of drug concentrations in postmortem blood--a case study

A 25-year-old female died from a suicidal overdose of imipramine, acetaminophen, codeine, diphenhydramine, and ethanol. Blood samples from ten segregated arterial and venous sites, twenty-four tissue samples, cerebrospinal fluid, vitreous humor, and bile were analyzed. Imipramine and desipramine, which were highly concentrated in the liver and lungs, each showed marked site dependent differences in blood concentrations. The highest concentrations were in pulmonary venous blood and the lowest in peripheral venous blood. Imipramine concentrations in the ten blood samples differed by as much as 760% (range 2.1 to 16.0 mg/L). Blood desipramine concentrations ranged from 1.4 to 10.6 mg/L. In contrast, blood concentrations of acetaminophen differed by less than 20% (55 to 65 mg/L) and blood ethanol concentrations ranged from 151 to 175 mg/100 mL. Blood concentrations of diphenhydramine ranged from 0.34 to 2.07 mg/L and codeine from 0.33 to 0.89 mg/L. The data illustrates that a marked site dependent variability in postmortem blood concentrations exists for some drugs but not others.