Editor’s Comment: In a recent survey conducted by ProHealth, one-third of the respondents reported that they experienced improvement while taking duloxetine (Cymbalta). An equal number reported that duloxetine made them feel worse. A final third reported no effect, or could not judge whether duloxetine had made them better or worse. These results roughly parallel those of a large survey undertaken in 2008 by the ME Association in Great Britain, in which 30%-38% of respondents reported that antidepressants, of all classes, made them feel worse. Doctors who have prescribed antidepressants to their FM and CFS or ME patients have noted inconsistent responses to these drugs, with roughly one-third reacting poorly.
By Lesley M. Arnold et al.
Objective: To assess the efficacy and safety of duloxetine in patients with chronic fatigue syndrome.
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Methods: A 12-week, randomized, double-blind study was designed to compare duloxetine 60-120?mg/day (n=30) with placebo (n=30) for efficacy and safety in the treatment of patients with chronic fatigue syndrome. The primary outcome measure was the Multidimensional Fatigue Inventory (MFI) general fatigue subscale (range 4–20, with higher scores indicating greater fatigue). Secondary measures were the remaining MFI subscales, Brief Pain Inventory (BPI), Medical Outcomes Study Short Form-36 (SF-36), Hospital Anxiety and Depression Scale (HADS), CDC Symptom Inventory, Patient Global Impression of Improvement (PGI-I), and Clinical Global Impression of Severity (CGI-S). The primary analysis of efficacy for continuous variables was a longitudinal analysis of the intent-to-treat sample, with treatment-by-time interaction as the measure of effect.
Results: The improvement in the duloxetine group on the MFI general fatigue scores was not significantly greater than the placebo group (P=0.23; estimated difference between groups at week 12 = ?1.0 [95% confidence interval ?2.8, 0.7]). The duloxetine group was significantly superior to placebo on the MFI mental fatigue score, BPI average pain severity and interference scores, SF-36 bodily pain domain, and CGI-Severity score. Duloxetine was generally well tolerated.
Conclusion: The primary efficacy measure of general fatigue did not significantly improve with duloxetine compared to placebo. Significant improvement in secondary measures of mental fatigue, pain, and global measure of severity suggests that duloxetine may be efficacious for some CFS symptom domains, but larger, controlled trials are needed to confirm these results.
: Lesley M. Arnold, Thomas J. Blom, Jeffrey A. Welge, Elizabeth Mariutto, Alicia Heller. Psychosomatics
. Published Online: December 16, 2014. DOI: http://dx.doi.org/10.1016/j.psym.2014.12.003