Duloxetine for Chronic Low Back Pain Evaluated

J Pain Res; 2017 Jul 24; Alev, et al

August 22, 2017

Week ending August 27, 2017

Patients treated with duloxetine for chronic low back pain (CLBP) with multiple painful sites had more benefit than patients with isolated CLBP, and early pain reduction was predictive of response for all patients. This according to a recent post hoc responder analysis of 4 double-blind, randomized, placebo-controlled trials of duloxetine (60 mg/day for 12-14 weeks) in adults patients with CLBP. Primary outcome was proportion of patients with ≥30% reduction in Brief Pain Inventory (BPI) average pain at 12-14 weeks. The proportion of patients with ≥30% and ≥50% (secondary outcome) pain reduction in duloxetine and placebo groups was compared.

• Compared with placebo (n=653), a greater proportion of duloxetine-treated patients (n=642) achieved ≥30% and ≥50% pain reduction.
• Early improvement among patients treated with duloxetine was associated with greater likelihood of ≥30% or ≥50% pain reduction.
• Women were slightly more likely than men to achieve ≥30% or pain reduction.
• Patients with ≥2 painful sites were more likely to respond to duloxetine 60 mg relative to placebo than patients with isolated CLBP.

Citation:

Alev L, Fujikoshi S, Yoshikawa A, et al. Duloxetine 60 mg for chronic low back pain: post hoc responder analysis of double-blind, placebo-controlled trails. J Pain Res.2017;10:1723-1731. doi:10.2147/JPR.S138297.

Commentary:

CLBP is a challenging problem. Treatment typically includes analgesics such as acetaminophen, NSAIDs, opioids, and adjuvant pain medications, as well as physical modalities including stretching, exercise, and physical therapy. With increased recognition of the side effects of NSAIDs, and risks of addiction with opioids, the use of adjuvant pain medications like duloxetine has become increasingly sigificant. One theory holds that a significant number of patients with CLBP have pain secondary to changes in the central nervous system processing of pain.1,2 For this reason, duloxetine has been studied in double-blind, randomized, placebo-controlled trials of CLBP and has shown positive outcomes.3 If patients who are likely to have central sensitization as an important contributor to their pain can be identified ahead of time, then we might have a higher chance of effectively treating their pain with adjuvant pain medications, including duloxetine. The current post-hoc analysis suggests that patients who have pain in multiple areas may have a higher probability of response to duloxetine than those who have only low back pain, and those who have some response within 2 weeks have a higher chance of long-term response than those who do not respond within a couple of weeks of starting medication. This ability to predict the likelihood of response to duloxetine may be clinically helpful in choosing therapy for this common but difficult to treat condition. —Neil Skolnik, MD

1. Clauw DJ. Diagnosing and treating chronic musculoskeletal pain based on the underlying mechanism(s). Best Pract Res Clin Rheumatol. 2015;29(1):6–19. doi:10.1016/j.berh.2015.04.024.

2. Phillips K, Clauw DJ. Central pain mechanisms in chronic pain states - maybe it is all in their head. Best Pract Res Clin Rheumatol. 2011;25(2):141–154. doi:10.1016/j.berh.2011.02.005.
3. Skljarevski V, Desaiah D, Liu-Seifert H, et al. Efficacy and safety of duloxetine in patients with chronic low back pain. Spine (Phila Pa 1976). 2010;35(13):E578–E585. doi:10.1097/BRS.0b013e3181d3cef6.