Table 3.

Mean pharmacodynamic parameters (95% confidence interval).

Parameter	Morphine+OND	Morphine+NS	Difference*
Threshold (°C)	44.7	44.8	0.09
	(43.7,45.7)	(43.8,45.8)	(−0.49,0.66)
Tolerance (°C)	46.5	46.7	−0.04
	(45.6,47.7)	(45.7,47.6)	(−0.48,0.41)
Temporal summation	7.2	7.7	−0.45
(# pulses to maximum pain)	(5.6,8.8)	(6.4,8.9)	(−1.44,0.53)
Mood score (cm)	2.1	2.0	−0.13
	(1.1,3.1)	(1.0,3.0)	(−1.23,0.96)

OND, ondansetron; NS, normal saline solution.

^*Difference of the least squares means [morphine+ OND – morphine+placebo] (95% confidence interval).