Table 1.
ED50 values (95% confidence limits) for nalbuphine, oxycodone, and ketamine alone or in combination in assays of capsaicin-induced thermal allodynia and scheduled-controlled responding in rhesus monkeys. Numbers in parentheses denote the number of subjects contributing to the ED50 value if less than the total number of monkeys tested (n=3) and the > symbol denotes a drug mixture for which an ED50 value could not be determined in all subjects tested.
| Drug or drug mixture | Nalbuphine ED50 (95% CL) |
Potency Ratio (95% CL) |
Ketamine ED50 (95% CL) |
|---|---|---|---|
| Capsaicin-induced thermal allodynia | |||
| Nalbuphine Alone | 0.05 (0, 0.36) | – | |
| Ketamine Alone | – | 0.53 (0.31, 0.91) | |
| 1:3.3 Nalbuphine/Ketamine | 0.03 (0.02, 0.04) | 1.38 (−2.91, 5.66) | 0.11 (0.08, 0.15) |
| 1:10 Nalbuphine/Ketamine (n=2) | > 0.06 (0.03, 0.1) | > 0.65 (0.1, 4.15) | |
| 1:33 Nalbuphine/Ketamine (n=2) | > 0.04 (0, 0.17) | > 1.29 (0.07, 24.12) | |
| Schedule-controlled responding | |||
| Nalbuphine Alone | 0.7 (0.25, 1.96) | – | |
| Ketamine Alone | – | 0.86 (0.70, 1.06) | |
| 1:3.3 Nalbuphine/Ketamine | 0.18 (0.09, 0.35) | 0.28 (−0.06, 0.63)a | 0.59 (0.30, 1.16) |
| 1:10 Nalbuphine/Ketamine | 0.12 (0.08, 0.17) | 0.21 (−0.24, 0.66)a | 1.15 (0.80, 1.67) |
| 1:33 Nalbuphine/Ketamine | 0.04 (0.02, 0.06) | 0.07 (−0.07, 0.20)a | 1.12 (0.71, 1.79) |
a
Potency shifts were considered statistically significant if the 95% confidence limits of the potency ratios did not include 1.