Hi everyone! I want to represent primary care in the Chief Blog, so I decided to put together this piece on a versatile medication to help a variety of common outpatient diagnoses. First and foremost, I have no financial disclosures, including to this med. Pain is difficult for physicians and patients alike. It’s tough to quantify, and there’s no lab gold standard physical exam or lab test we can order. It can be treatment-resistant. Clinical trials may look at 30% or 50% reduction in pain (not resolution) on Likert scales or changes in questionnaire scores. While studying for boards I learned about the many different indications for duloxetine, including the different types of pain it can treat.
I knew SNRIs could be used for MDD and GAD, and was somewhat familiar with their role in treating neuropathic pain. During my residency training it seemed like gabapentin, a TID medication, was often the first choice for neuropathic pain. However a 2011 Cochrane Review found a NNT 5.9 for gabapentin to achieve a 50% reduction in pain at 8-12 weeks. Duloxetine, dosed at once a day, had a NNT 6 for that outcome. The once daily dose of duloxetine, especially when combined with some of the other effects of the medication, makes it an excellent consideration!
Most surprising to me was the FDA approval of duloxetine for chronic low back pain and osteoarthritis. In my opinion the data for these indications is not as deep or longitudinal when compared to MDD, GAD, or neuropathic pain, but it’s interesting to think about using duloxetine as an adjunct to act on the descending pain modulatory pathway. Annals of Internal Medicine published a systematic review in 2017 that found duloxetine resulted in a small decrease in nonradicular chronic low back pain and an improvement in function. Separate studies have found improvement in osteoarthritis pain, with knee OA being the most studied.
As with any medication, there are associated side effects and adverse events, such as GI upset, dry mouth, and drowsiness. Please read the package insert for more specifics. I hope this piece makes you think more about a single agent for these common conditions!
My key takeaway is this medication can be used for MDD, GAD, neuropathic pain, chronic low back pain, and osteoarthritis.
Moore RA, Wiffen PJ, Derry S, McQuay HJ. Gabapentin for chronic neuropathic pain and fibromyalgia in adults. Cochrane Database Syst Rev. 2011;(3):CD007938. doi:10.1002/14651858.CD007938.pub2.
Lunn MP, Hughes RA, Wiffen PJ. Duloxetine for treating painful neuropathy, chronic pain or fibromyalgia. Cochrane Database Syst Rev. 2014;(1):CD007115. doi:10.1002/14651858.CD007115.pub3.
Chou R, Deyo R, Friedly J, et al. Systemic Pharmacologic Therapies for Low Back Pain: A Systematic Review for an American College of Physicians Clinical Practice Guideline. Ann Intern Med. 2017;166(7):480-492. doi:10.7326/M16-2458.