. Author manuscript; available in PMC: 2010 Jan 5.

Published in final edited form as: Eur J Pharmacol. 2008 Nov 11;602(1):92–100. doi: 10.1016/j.ejphar.2008.11.004

Table 3.

ED50 values in mg/kg (95%CL) for fentanyl and a delta opioid administered alone or as part of a mixture in the assay of thermal nociception. ^abIndicates ED50 confidence limits for fentanyl or delta opioid in mixture do not overlap with ED50 confidence limits for fentanyl or delta opioid alone. ^aED50 in mixture lower than ED50 for drug alone. ^bED50 in mixture higher than drug alone.

	Fentanyl	Delta Opioid
Treatment	ED50 (95%CL)	ED50 (95%CL)

Fentanyl Alone	0.015 (0.010-0.021) ^a
SNC243A Alone		Inactive
5:1 SNC/Fent	0.004 (0.003-0.006) ^a	0.022 (0.015-0.032) ^a
15:1 SNC/Fent	0.004 (0.003-0.007) ^a	0.063 (0.040-0.100) ^a
45:1 SNC/Fent	0.006 (0.006-0.006) ^a	0.250 (0.247-0.254) ^a
Fentanyl Alone	0.017 (0.013-0.023)
MSF61 Alone		Inactive
30:1 MSF/Fent	0.019 (0.013-0.028)	0.57 (0.38-0.84) ^a
89:1 MSF/Fent	0.017 (0.013-0.021)	1.48 (1.19-1.83) ^a
267:1 MSF/Fent	0.021 (0.018-0.025)	5.71 (4.81-6.77) ^a
Fentanyl Alone	0.017 (0.013-0.023)
Naltrindole Alone		Inactive
4:1 NTI/Fent	0.024 (0.024-0.024)†	0.096 (0.095-0.096) ^a
12:1 NTI/Fent	0.023 (0.20-0.028)	0.28 (0.24-0.33) ^a
36:1 NTI/Fent	>0.069^b	>2.49