Effects of topical morphine on systemic and spinal morphine analgesia
| Morphine Route | ED50 (95% CL) | Topical Shift |
|---|---|---|
| Systemic alone (mg/kg) | 4.3 (2.9–6.4) | |
| Systemic + topical (mg/kg) | 0.66 (0.4–1.0) | 6.5 |
| Spinal alone (ng) | 550 (386–822) | |
| Spinal + topical (ng) | 46 (21–84) | 12 |
ED50 values and 95% confidence limits were determined for morphine given systemically alone or in conjunction with a fixed dose of topical morphine (15 mM). Testing was done 30 min after the treatments, at which point there were no observable effects from the topical morphine alone. ED50 values and 95% confidence limits were determined for morphine given intrathecally alone and with a fixed dose of topical morphine (15 mM). Testing was done 15 min after the treatments, at which point the topical morphine had only a limited (15%) response.