Apparent suicidal carbon monoxide poisonings with concomitant prescription drug overdoses

We report four separate suicides by apparent motor vehicle-related carbon monoxide (CO) poisoning in which complete toxicological analysis showed the absence of, or lower than expected, percent carboxyhemoglobin saturation and high concentrations of concomitant prescription drugs. These cases, within a population of 71 apparent CO suicides from the Wayne County Medical Examiner's Office over 1998-2004, represent cases where additional factors are in play. Multiple modalities (CO poisoning and drug overdose) and/or undetectable carbon dioxide poisoning from the vehicle exhaust of cars manufactured after laws regulating vehicle emissions were enacted are examples of additional factors that require consideration in these selected cases. All four cases demonstrated some degree of decomposition, so the possible loss of CO could not be ruled out. The need for full toxicological analysis in apparent suicidal CO poisoning is emphasized.