Toxicology testing revealed dramatic increases in whole-blood concentrations of verapamil and diphenhydramine in the short time between hospital admission and death (53 min) in a subject (with a history of overdosing) found unresponsive. While some degree of post-mortem redistribution (PMR) would be expected for the drugs found in this case, PMR cannot explain the considerable increases observed. It is recommended that in potential overdose cases without a clear manner of death but for which ante-mortem and post-mortem specimens (including gastric content) are available, all should be analysed and considered in order to make a more definitive conclusion regarding that death.