Post-mortem drug concentrations.

Considerable changes occur in the concentrations of numerous drugs after death. Some concentrations increase, others fall and some do not change. Active agents, such as gamma hydroxybutyrate and alcohol, may be synthesized in the deceased body. Many published tables contain lists of therapeutic, toxic and lethal concentrations that are misleading. While the process of post-mortem redistribution of drugs has been called a 'toxicological nightmare', it is still possible to obtain a lot of information from the integration of ante-mortem history with the post-mortem drug concentration.