Table 1.
Predicted additive ED50, ED25, and ED75 values (Zadd) and experimentally determined ED50, ED25, and ED75 values (Zmix) for oxycodone and nalfurafine mixtures from a measure of thermal antinociception (Experiment 3).
| Effect Level | Zadd (95% CL) | Zmix (95% CL) | Relationship |
|---|---|---|---|
| ED50 | |||
|
| |||
| 175:1 | 2.3 (1.3–3.4) | 1.8 (1.3–2.2) | Additive |
| 56:1 | 1.6 (0.9–2.3) | 1.2 (0.4–2.1) | Additive |
| 18:1 | 0.8 (0.5–1.1) | 0.5 (0.3–0.6) | Additive |
| ED25 | |||
|
| |||
| 175:1 | 1.1 (0.5–1.8) | 1.2 (0.9–1.5) | Additive |
| 56:1 | 0.6 (0.3–0.9) | 0.8 (0.2–1.4) | Additive |
| 18:1 | 0.2 (0.1–0.3) | 0.3 (0.2–0.4) | Additive |
| ED75 | |||
|
| |||
| 175:1 | 4.3 (2.5–6.0) | 2.6 (1.9–3.3) | Additive |
| 56:1 | 3.5 (2.1–4.9) | 2.1 (1.0–3.2) | Additive |
| 18:1 | 2.2 (1.3–3.1)* | 0.7 (0.5–0.8)* | Synergistic* |
*
indicates a significant difference between Zadd and Zmix (non-overlapping 95% confidence limits). If Zadd > Zmix, a supra-additive interaction is suggested. Conversely, if Zadd < Zmix, a sub-additive interaction is suggested.