Milnacipran for Chronic Pain in Knee Osteoarthritis

Total target dose of 200 mg/day. Subjects will titrate-up according to the following schedule: 25 mg/d (2 pills, 2 days), 50mg mg/d (4 pills, 2 days), 100mg/d (2 pills, 3 days), 150 mg/d (3 pills, 4 days), and steady state is reached once the study participant ingests 200 mg/d(4 pills). The steady state is maintained for 44 days (approx. 6 weeks). If intolerable side effects occur, the dose may be reduced to last tolerable does, a minimum of 100 mg/day at the discretion of the PI. Subjects unable to tolerate 100 mg/day will be discontinued from the study. A 2-week down-titration will be used.

Subjects will receive identical placebo pills and dosing schedule as that of participants receiving active study medication.