Effect of High-dose Naloxone Infusion on Pain and Hyperalgesia in Patients Following Groin-Hernia Repair.

Recent studies have focused on the role of endogenous opioids on central sensitization. Central sensitization is known to be impaired or altered in chronic pain conditions, as fibromyalgia or chronic tension headache. Animal studies have shown reinstatement of mechanical hypersensitivity following naloxone administration after resolution of an injury. This suggests latent sensitization. In the present study, investigators hypothesize that a high-dose target-controlled naloxone infusion (total dose: 3.25 mg/kg) can reinstate pain and hyperalgesia 6-8 weeks after a unilateral primary open groin hernia repair procedure. Investigators aim to show that latent sensitization is present in humans and is modulated by endogenous opioids.