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Completed

NCT Number: NCT01594047

Perioperative Opioid-induced Hyperalgesia and Its Prevention With Ketamine and Methadone

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.

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Key information

Conditions

Post Operative Pain Hyperalgesia Nervous System Diseases Neurologic Manifestations Pain Pain, Postoperative Pathologic Processes Pathological Conditions, Signs and Symptoms Postoperative Complications Sensation Disorders Signs and Symptoms Somatosensory Disorders

Age range

18 year–75 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Fondazione IRCCS Istituto Nazionale dei Tumori

Milan, 20133, Italy

About this study

not desired

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

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.

Treatment and study plan

ketamine infusion

Drug

Ketamine infusion scheme: 5mcg/Kg/min from induction od anaesthesia for 10 min, than 2,5mcg/Kg/min for 20 min and than 2 mcg/Kg/min to the end of surgery

Other names: hyperalgesia-blocker

Methadone PCA

Drug

Methadone administered by a PCA system (dose 2 mg, lock-out 12min.)

Other names: hyperalgesia-blocker

Primary outcomes

  1. the Extent of Hyperalgesia Area Proximal to Surgical Wound

    Time frame: 24 and 48 hours after surgery

    Hyperalgesia is determined by stimulating with a won Fray hair N°16 along three lines at a right angle to the top, middle, and bottom sides of the surgical incision. Each line starts from the edge of the abdomen to the surgical incision.

    Stimulation continue from the edge toward the surgical incision until the patients reported a worsening in sensation The distance from the incision to where sensation change was measured. The mean of the three assessments was used as a measure of the extent of the hyperalgesia area.

Secondary outcomes

  1. Pain Intensity Measured by a Numeric Rating Scale (NRS)

    Time frame: 24 and 48 hours after surgery

    A Numerical Rating Scale (NRS) from 0 to 10 is used as a measure of pain intensity. Zero indicates the absence of any pain and 10 the worse pain never felt.

  2. Opioid Consumption

    Time frame: 48 hours

    Cumulative opioid consumption at 48 hours from surgery ( end of the study)

Sponsors and collaborators

Lead sponsor

Fondazione IRCCS Istituto Nazionale dei Tumori, Milano

Other

Registry information

Important dates

Study start
2009
Primary completion
2012
Study completion
2014
First posted
May 8, 2012
Registry last updated
Oct 1, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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