Table 1.

Clinically observed methadone tissue concentrations.

Application	Incidence	Daily Oral Dose [mg]	Organ	Methadone [µM]	Patient Number	Ref.
anti-glioma therapy	methadone maintenance	30	blood	0.59–0.67	1	[19]
drug substitution	methadone maintenance	83.3 *	blood	1.5 * 2 #	104	[46]
drug abuse	methadone-associated death		Blood	2.6 * 14.5 #	17	[38]
			brain	12.0 *,$	17
drug substitution/drug abuse	methadone-associated death	20–80	Blood	1.6 ** 10.6 #	15	[37]
			brain	2.2 **,$ 8.6 #,$	15
			CSF	0.7 ** 2.8 #	8
drug substitution/drug abuse	§ methadone-associated death		blood	2.6 * (2.3 **) 8.5 #	52	[47]
drug substitution/drug abuse	§ methadone-associated death		blood	1.3 * (2.3 **) 9.7 #	11	[48]

^$ roughly estimated from ng/g data under the assumption of equal distribution between all intracellular and extracellular compartments; * mean; ** median; ^# highest value; ^§ not in combination with other drugs; CSF: cerebrospinal fluid.