Drug concentration in selected skeletal muscles

We evaluated the homogeneity of drug concentrations in muscle in 14 cadavers, comprising 11 drug overdoses and three cases of chronic therapeutic drug use. Analyses were performed on samples from twelve named muscles and femoral venous blood. Standard analytical techniques and instrumentation were used throughout. There was marked within-case variability in drug concentrations with highest:lowest concentrations ranging up to 21.7. Overall highest concentrations were found in the diaphragm and mean diaphragm:blood ratios ranged from 1.1 (temazepam, two cases) and 1.2/1.3 (paracetamol, six cases) up to 6.5/13.5 (amitriptyline, three cases) and 5.3/21.3 (propoxyphene, four cases). Excluding the diaphragm, mean muscle:blood ratios ranged from 0.4 (prothiaden), 0.5 (temazepam), and 0.7 (paracetamol) up to 3.7 (temazepam), 4.3 (propoxyphene) and 5.7 (amitriptyline). We suggest that muscle is suitable for qualitative analysis but not for quantitative corroboration of a blood sample or as a quantitative alternative to blood.