Effect of Nefopam on Remifentanil Induced Postoperative Hyperalgesia

Study Overview
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Brief Summary
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Opioids has been reported to cause hyperalgesia. Opioid induced hyperalgesia (OIH) is defined as paradoxically lowering the threshold of pain after the exposure of opioid. Remifentanil is a short acting opioid that is commonly used during anesthesia and surgery. However, OIH was reported to occur after surgery when large amount of remifentanil was administered. On the other hand, nefopam is a centrally acting, non-opioid analgesic. Nefopam has been reported to have analgesic and anti-hyperalgesic effect. The investigators hypothesized that nefopam administration could prevent OIH or reduce the severity of OIH. Therefore, the objective of the study is to find out the effect of nefopam on remifentanil induced hyperalgesia in patients undergoing laparoscopic abdominal surgery.

Conditions
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Patients Undergoing Laparoscopic Gastrectomy

Intervention / Treatment
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* Drug: Nefopam
* Drug: low dose remifentanil
* Drug: high dose remifentanil


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients undergoing laparoscopic gastrectomy American Society of Anesthesiologists physical status I or II aged from 20 to 65 years Exclusion Criteria: Past history of chronic pain Drug or alcohol abuse Psychotic disorder Taking analgesics, anti-epileptics, and anti-depressants. Taking opioids within 24 hrs Renal disease Neuromuscular disease. Moderate to severe cardiovascular disease Pregnant or breast-feeding

Ages Eligible for Study
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Minimum Age: 20 Years
Maximum Age: 65 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Supportive Care
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Placebo Comparator: group L<br>receives 100 ml of 0.9% saline immediately after anesthesia induction and 0.05µg/kg/min of remifentanil during anesthesia. | Drug: low dose remifentanil<br>* 100 ml of 0.9% saline immediately after anesthesia induction and 0.05µg/kg/min of remifentanil during anesthesia.<br>|
| Placebo Comparator: group H<br>100 ml of 0.9% saline immediately after anesthesia induction and 0.3 µg/kg/min of remifentanil during anesthesia. | Drug: high dose remifentanil<br>* 100 ml of 0.9% saline immediately after anesthesia induction and 0.3 µg/kg/min of remifentanil during anesthesia.<br>|
| Experimental: group N<br>20mg of nefopam mixed in 100 ml of 0.9% saline immediately after anesthesia induction and 0.3 µg/kg/min of remifentanil during anesthesia. | Drug: Nefopam<br>* 20 mg of Nefopam mixed in 100 ml of 0.9% saline IV immediately after induction of anesthesia.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Hyperalgesic extent around surgical incision | The distance from the surgical incision to a point where patient does not feel pain when he gets stimuli with von Frey filament No.16 (122g/mm2). | Postoperative 24 hr and 48 hr | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Opioid-induced hyperalgesia (OIH)