Eligibility

Ages Eligible for Study

18 years to 75 years

Genders Eligible for Study

Both

Keywords

hyperalgesia, Patient controlled analgesia, morphine, methadone, and ketamine

Sponsors

Other

Fondazione IRCCS Istituto Nazionale dei Tumori, Milano

Inclusion Criteria

- patients undergoing open colo-rectal surgery

Exclusion Criteria

- ASA status more than II, history of chronic pain, ischemic heart disease or chronic
pulmonary disease, allergy to any drugs used in the protocol. Body Max Index more
than 35.

Detailed Description

Background: In perioperative period inhibition of N-Methyl-D-Aspartate receptor prevents opioid-induced hyperalgesia and reduce postoperative opioid requirement after abdominal surgery. Methadone is both a µ-opioid receptor agonist like Morphine and a N-Methyl-D-Aspartate antagonist. Study Aim. To evaluate the efficacy of intraoperative Ketamine and postoperative Methadone analgesia in preventing opioid-induced hyperalgesia after abdominal surgery.