Table 3.

Change in numerical rating scale score in relation to the COMT allelic status stratified to the bolus dose of morphine (i.e. 2.5 or 7.5 mg)

Genotype	Change in numerical rating scale score	P value
Morphine dose 2.5 mg
Val/Val	+0.1 ± 1.9	0.79
Val/Met	−1.3 ± 1.6	<0.001
Met/Met	−2.0 ± 3.2	0.04
Morphine dose 7.5 mg
Val/Val	−1.0 ± 1.3	0.11
Val/Met	−1.0 ± 2.7	0.04
Met/Met	−1.3 ± 1.7	0.02

All values are expressed as means ± SD.