TABLE 4.

Dose ratios of 2-BFI alone, opioids alone, and 2-BFI+opioid mixtures to produce antinociception versus suppression of operant responding

	Mechanical	Thermal
2-BFI alone	1.39	0.99
Fentanyl alone	4.00*	2.00*
1:3 2-BFI/fentanyl	4.63a,*	1.55*
1:1 2-BFI/fentanyl	2.07*	0.80
3:1 2-BFI/fentanyl	2.06*	0.93
Buprenorphine alone	<0.43	10.00
1:3 2-BFI/buprenorphine	3.71a,*	1.47*
1:1 2-BFI/buprenorphine	3.96a,*	0.85
3:1 2-BFI/buprenorphine	1.07	0.66
NAQ alone	<0.35	<0.35
1:3 2-BFI/NAQ	2.17a,*	0.80
1:1 2-BFI/NAQ	3.46a,*	1.05a
3:1 2-BFI/NAQ	1.57a	0.85

^aDose ratio for a combination is greater than dose ratio for either component drug.

^*Drug or drug mixture was significantly more potent in the assay of nociception as determined by nonoverlapping confidence limits of Z_mix values.