Inclusion Criteria:  Any patient undergoing primary total knee arthroplasty for osteoarthritis Age ≥ 18 years old Willingness to undergo randomization and return for all scheduled visits English speaking  Exclusion Criteria:  Age > 80 years old American Society of Anesthesiologists (ASA) Score ≥ 4 Prior use of SSRIs or SNRIs Use of serotonergic drugs in the past 6 months with the exception of tramadol Known psychiatric disorder (specifically: generalized anxiety disorder, major depressive disorder, type I or type II bipolar disorder, and schizophrenia) Heavy alcohol consumption defined as ≥ 14 drinks per week for men and ≥ 7 drinks per week for women Opioid tolerant patients defined as ≥ 60 morphine equivalents (MEQs) per day within 90 days prior to surgery Renal impairment defined as a glomerular filtration rate (GFR) < 30 mL/minute or creatinine >1.3 mg/dL Non-English speaking Non-independent (i.e. requires a caretaker to make medical decisions on their behalf)