Memantine and Postoperative Pain

Study Overview
=================
Brief Summary
-----------------
Memantine is associated with improvement in pain relief after surgery.

Detailed Description
-----------------
This prospective, randomized, controlled trial will investigate whether perioperative memantine has a postoperative analgesic effect following radical retropubic prostatectomy (RRP). 100-110 patients scheduled to undergo RRP at Duke will be assessed preoperatively for allodynia using Von Frey filaments, then stratified into two groups based on the presence or absence of allodynia. Patients in each group will then be randomized to receive either memantine 20 mg or placebo 30-60 minutes preoperatively, followed on postoperative day 1 with either memantine 10 mg in the morning and 10 mg in the evening for memantine patients, or placebo at the same intervals for placebo patients. Data such as morphine consumption, patient satisfaction and pain scores, opioid-related side effects, and the area of hyperalgesia around the surgical incision will be recorded for the initial 48 hours postoperatively, and patient satisfaction with their postoperative analgesia will be assessed after 1 week. At 1, 3, and 6 months postoperatively, patients will be asked about the presence and intensity of any persistent pain related to surgery.

Official Title
-----------------
Memantine for Postoperative Analgesia

Conditions
-----------------
Pain

Intervention / Treatment
-----------------
* Drug: Memantine
* Drug: Placebo


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: Male Age 18 to 75 years old Exclusion Criteria: Chronic pain conditions or taking regular analgesics Taking psychotropic medications Parkinson's disease Narrow-angle glaucoma Known gastroduodenal ulcer History of seizure disorder Renal insufficiency, as defined by serum creatinine greater than 2 mg/dL Liver disease, including liver failure, cirrhosis, or acute hepatitis Significant coronary vascular disease or cardiac conduction system disease, as noted by ECG or history of cardiac symptoms, or cardiac ejection fraction less than 30% American Society of Anesthesiologists (ASA) score of 4 or higher Allergy to ketorolac or memantine

Ages Eligible for Study
-----------------
Minimum Age: 18 Years
Maximum Age: 75 Years

Sexes Eligible for Study
-----------------
Male

Accepts Healthy Volunteers
-----------------
No

Study Plan
=================
How is the study designed?
-----------------

Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Quadruple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Memantine<br> | Drug: Memantine<br>* 20 mg, BID<br>|
| Placebo Comparator: Placebo<br>Placebo | Drug: Placebo<br>* BID<br>|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| 24 hr Opioid Consumption |  | 24 hr | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Pain Scores | Pain score (0=no pain, 10= worst possible pain) | 48 hours | 
| Opioid Related Side Effects | Number of participants with postoperative nausea and vomiting. | 0-24 h | 
| Opioid Related Side Effects: Pruritus | Number of participants who experienced pruritus. | 0-24 h | 
| Hyperalgesia | Stimulation with a Von Frey hair filament at 396 mN of force will be started from outside the hyperalgesic area, where no pain sensation is experienced toward the incision until the patient reports a distinct change in perception. The first point where a painful, sore, or sharper feeling occurs will be marked, and the distance to the incision measured. The surface area will be measured in cm2 around the surgical incision. | Within 48 h | 
| Patient Satisfaction | Number of participants who reported very satisfied or somewhat satisfied | 48 hours | 
| Chronic Post-surgical Pain |  | 1 month, 3 month, 6 month |