Figure 6.
No exacerbation of CCI allodynia by morphine, oxycodone, or fentanyl when dosing begins 1 hour after injury. Chronic constriction injury was performed with one chromic gut 6–0 suture. Morphine (5 mg/kg twice per day), (fentanyl (0.01 mg/kg/h), oxycodone (2 mg/kg twice per day), or equivolume saline was administered for 5 days, beginning at one-hour after surgery. (A) Von Frey testing was conducted before and after CCI surgery, and after completion of opioid administration. (B) Area-under-curve analysis of von Frey threshold of all timepoints after opioid treatment. BL, baseline. n = 6/group. CCI, chronic constriction injury.