Accumulation of intravenously administered methamphetamine in stomach contents

The accumulation of intravenously administered methamphetamine (MAMP) in the stomach contents was investigated as part of a process used to discriminate between oral and intravenous administration of MAMP. Eight forensic autopsy cases, in which intravenous administration of MAMP was confirmed, were used. Total amounts and pH values of stomach contents were in the ranges of 20–500 g and 3–5 (determined in seven cases), respectively. Intervals between the last MAMP administration and each death could be roughly estimated in four cases: 1–3 h in two cases and 3–6 h in two cases. MAMP levels in stomach contents and whole blood were in the ranges of 0.816–43.4 µg/g (total amounts: 0.114–1.95 mg) and 0.236–14.6 µg/ml, respectively. The mean ratio of MAMP level in the stomach contents to that in whole blood was 8.23 ± 9.01, indicating accumulation of MAMP in the stomach contents against a concentration gradient. On the basis of the average plus three times the standard deviation, a tentative borderline ratio value for discriminating oral and intravenous administrations of MAMP was calculated to be 36. When the ratio is 36 or larger, a deceased can be diagnosed to have used MAMP orally; when it is smaller than 36, either possibility (oral or intravenous route) is considered possible.