Table 2. Plasma _unbound and brain _unbound concentrations of atomoxetine in absence or presence of morphine; esreboxetine in absence or presence of morphine and/or fluoxetine; fluoxetine in absence or presence of morphine and/or esreboxetine; and duloxetine in absence or presence of morphine and ondansetron - at 75 min post-dosing.

Dose (mg/kg)	[Plasma]unbound (ng/ml)	[Brain]unbound (ng/g)
	Atomoxetine 10 mg/kg
− Morphine	50.9±5.8	58.2±10.9
+ Morphine 3	57.9±12.5	52.6±14.4
	Esreboxetine 10 mg/kg
− Fluoxetine - Morphine	33.4±12.2	20.4±14.4
+ Morphine 1	21.0±17.7	12.7±9.9
+ Fluoxetine 1+ Morphine 1	31.2±8.6	25.0±5.8
	Fluoxetine 1 mg/kg
− Esreboxetine - Morphine	1.73±1.5	1.94±1.2
+ Morphine 1	0.96±0.3	1.36±0.6
+ Esreboxetine 10+ Morphine 1	1.51±0.5	1.55±0.6
	Duloxetine 5 mg/kg
− Ondansetron - Morphine	4.98±1.4	13.0±1.5
+ Ondansetron 3	3.51±1.2	12.8±4.5
+ Ondansetron 3+ Morphine 1	4.55±0.7	16.5±4.1

n = 3–6 for each group. Data are presented as mean ± standard deviation.