Effect of Duloxetine on Opioid Use After Total Knee Arthroplasty

Phase 4

Completed

Brief Summary: Post-discharge pain after total knee arthroplasty remains problematic; many patients have excessive pain at the 2 week time point (and often thereafter). Reduction in opioid use has become a national goal, due to the 'epidemic' in opioid misuse.

In addition to enrolling non-opioid users, we will enroll up to 15 chronic opioid users.

Recruitment & Eligibility

Inclusion Criteria

Age 25 to 75 years
Planned use of regional anesthesia
Ability to follow study protocol
English speaking (Primary outcome obtained via telephone call and secondary outcomes include questionnaires validated in English only)
Patients planning on being discharged home or to a rehabilitation center that has agreed to participate

Exclusion Criteria

Current Use of duloxetine or other SNRIs, SSRIs, MAOIs, Tricyclic antidepressants, triptans (sumatriptan, rizatriptan, naratriptan, eletriptan, almotriptan, frovatriptan), lithium, buspirone, St. John's Wort
Hepatic insufficiency

o Hepatoxicity is reported as a side effect of duloxetine. "Median time to detection of transaminase elevation was about two months" (package insert 5.2
Renal insufficiency (ESRD, HD, estimated creatinine clearance < 50 ml/min)
- Severe CRI may impair duloxetine clearance
- CLcr=[(140-age (years)] x weight (kg)x0.85 (for female patients)/[72xserum creatinine (mg/dL)]
Patients younger than 25 years old and older than 75
Patients intending to receive general anesthesia
Allergy or intolerance to one of the study medications
Patients with an ASA of IV
Chronic gabapentin/pregabalin use (regular use for longer than 3 months)
Patients with major prior ipsilateral open knee surgery.
Chronic opioid use (taking opioids for longer than 3 months)
- However, patients using chronic opioids may enroll in a parallel pilot study entitled 'effect of duloxetine on opioid use after total knee athroplasty among patients exposed to opioids- a pilot study'. The chronic opioid users will be allowed to continue their customary analgesics. The pilot study is otherwise identical to the main study.
- This study will enroll up to 15 chronic opioid users. After that, all chronic opioid users are excluded.

Arm && Interventions

Group	Intervention	Description
Duloxetine ("Cymbalta")	Cymbalta	Epidural analgesia after knee arthroplasty is not as prevalent at HSS as formerly, in large part due to the rise of local infiltration analgesia. Studies using epidural analgesia may also lack generalizability given the infrequent use of epidural analgesia at other institutions. For these reasons, we plan to use adductor canal nerve blockade + local infiltration analgesia for management of immediate postoperative pain. Patients will receive spinal anesthesia as the primary anesthetic. It is particularly important to study duloxetine ("Cymbalta") in the context of local infiltration analgesia, as patients receiving local infiltration analgesia receive increased doses of opioids, compared to patients receiving epidural analgesia.
Placebo	Placebo	Placebo to compare pain scores and opioid use againts Duloxetine

Primary Outcome Measures

Name	Time	Method
Opioid Use	Post-operative day 14	Opioid use (measured in cumulative morphine equivalents)
Pain Scores	Post-operative day 14	Numerical Rating Score pain with movement. Minimum value of 0, maximum value of 10. Higher scores mean more pain and worse outcome.

Secondary Outcome Measures