Investigation of the potentiation of the analgesic effects of fentanyl by ketamine in humans: a double-blinded, randomised, placebo controlled, crossover study of experimental pain[ISRCTN83088383]

Table 4 Measured Serum Drug Concentrations

	Baseline		Concentration 1		Concentration 2		Concentration 3		Concentration 4
	Mean	SD	Mean	SD	Mean	SD	Mean	SD	Mean	SD
Propofol (μg/ml)	0.00	(0.00)	0.10	(0.04)	0.26	(0.07)	0.58	(0.18)	0.92	(0.24)
			0.11	(0.03)	0.31	(0.11)	0.62	(0.16)	0.91	(0.25)
Ketamine (ng/ml)	0.00	(0.00)	11.49	(4.31)	24.64	(6.68)	47.87	(18.03)	85.75	(31.87)
			12.61	(4.85)	27.48	(11.62)	51.86	(21.54)	93.88	(38.26)
Fentanyl (ng/ml)	0.00	(0.00)	0.28	(0.03)	0.53	(0.09)	1.01	(0.15)	1.48	(0.26)
			0.31	(0.07)	0.55	(0.13)	1.02	(0.21)	1.53	(0.25)
Ketamine (ng/ml)	0.00	(0.00)	25.59	(13.26)	30.29	(13.94)	30.73	(16.98)	29.88	(12.84)
			25.41	(5.76)	35.41	(15.90)	29.82	(12.26)	31.58	(14.23)
&
Fentanyl (ng/ml)	0.00	(0.00)	0.27	(0.11)	0.49	(0.13)	1.05	(0.17)	1.57	(0.26)
			0.29	(0.06)	0.57	(0.15)	1.09	(0.24)	1.57	(0.29)

SD denotes standard deviation. The upper and lower data in each cell represents the serum concentration measured at the beginning and at the end of each test battery respectively.

ISSN: 1471-2253