Introduction
Parkinson’s disease, hyperalgesia, pain
SECONDARY
The benefits of effective pain management after surgery and the favorable effect on fast recovery and outcome are well documented [Orphenadrine is a centrally acting muscle relaxant initially used for the treatment of Parkinson’s disease. In addition, it has anticholinergic and antihistaminic properties and a potential analgesic efficacy via an antagonistic effect on N‑methyl-D-aspartate (NMDA) receptors, as well as inhibiting effects on the norepinephrine re-uptake system. The exact mechanisms of its analgesic effects are unclear but a block of sodium channels could be a possible mechanism in its analgesic efficacy [The objective of this study was to investigate the potential opioid-sparing effect of a combination of diclofenac and orphenadrine versus diclofenac alone. We hypothesized that the addition of orphenadrine might also prevent opioid-induced secondary hyperalgesia after intraoperative use of potent opioids such as remifentanil.