As I have mentioned before, Cocaine is the #1 killer drug in Lake County. It is a very potent nervous system stimulant, which explains its euphoric and its lethal effects (in combination with its vascular effects). For some reason we have seen a bit of an up-tick in its lethal consequences recently. I don't know why and I don't know if it's a trend.
Cocaine is rapidly metabolized in the body, which makes it a bit tricky to catch in the bloodstream of a live individual. Usually, however, levels of Cocaine and/or its metabolites measured in bodily fluids after death give us the information we need to arrive at a determination of Cocaine-induced death. Most of the Cocaine consumed (inspired, injected, ingested) is metabolized in the liver, but Cocaine is relatively unique in that enzymes in blood cells also break it down, so Cocaine levels in the blood can drop after death and can even drop after blood is drawn and is in the lab tube. Cocaine's various metabolites are more stable in the blood and cocaine is relatively stable in the urine and vitreous (eyeball) fluid. Vitreous levels can be particularly helpful in reflecting brain levels.
We can get one bit of information if we find Cocaine in the blood we draw (or blood drawn in an ER before the individual dies). We then know that the individual likely consumed the cocaine a short time (at most, a few hours) before their death, because the half-life in the bloodstream (amount of time for one half of the substance to be cleared/metabolized) is thirty minutes. Through its vascular effects, primarily, Cocaine can kill several hours after consumption.
As our toxicology reports state "there are no safe levels of Cocaine". There is little doubt as to the cause/contribution to death when very high levels are found in the blood, urine, and/or vitreous fluid. But even lesser amounts kill individuals with heart electrical problems or vascular/circulatory abnormalities, or with risk of seizure or other neurologic abnormalities. Chronic Cocaine use can actually contribute to the development of these abnormalities, placing the user at increased risk of death.