Drugs that are approved by the Food and Drug Administration (FDA) go through clinical trials being evaluated in individuals who are the most ideal test subjects. As soon as a new medicine is approved by the FDA that same drug can be used in individuals who have more comorbidities like diabetes, hypertension, and depression. It is reassuring to know that post-approval populations of patients have a good response to a new medicine and no increase in the number of side effects.
Duloxetine is a medicine marketed as (Cymbalta, Irenka) that is used for the treatment of back pain that has both analgesic pain relieving qualities and works as an anti-depressant. Doctors recently reviewed the results of 3 randomized, double-blind clinical studies of patients receiving duloxetine or placebo for the management of chronic low back pain.1 A question that the authors wanted to answer was how much was duloxetine’s benefit related to its anti-depression properties versus its analgesic effects.
A total of 851 patients (400 duloxetine and 451 placebo) patients were included from 3 different studies. Duloxetine therapy resulted in significant decreases in chronic low back pain compared to placebo as measured by the Brief Pain Inventory. Depression scores were also improved. A mathematical technique ascribed 91.1% of the pain benefits were attributed to a direct analgesic effect and 8.9% to its antidepressant effect. Benefits were noted at week 4 in the evaluation.
Duloxetine is a form of therapy that is effective for the treatment of chronic low back pain. This is an important therapy for those individuals who have difficulties with other forms of back pain therapy like nonsteroidal anti-inflammatory drugs and opioids.
Reference: Enomoto H, Fujikoshi S, Funai J et al. Assessment of direct analgesic effect of duloxetine for chronic low back pain: post hoc path analysis of double-blind, placebo-controlled studies. J Pain Res 2017:10:1357-1368
David Borenstein, MD
Executive Editor The Spine Community.com