Two fatal cases involving concurrent use of methamphetamine and morphine

We report on two cases of simultaneous administration of methamphetamine (MAP) and morphine (MOR) with hyperthermia. The blood levels of MAP and MOR were toxic and putatively lethal, respectively, although hyperthermia is a known cause of intoxication due to MAP rather than MOR. In Japan, MAP is the most predominant cause of drug intoxication. The presented cases suggest that MOR may exert synergistic effect on hyperthermia due to the MAP intoxication, together with experimental findings.