Memantine and Postoperative Pain

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.

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