In a post hoc analysis of a pregabalin trial, researchers identified characteristics associated with pain improvement in patients with fibromyalgia who take antidepressant medications. Their findings were reported in Pain Medicine.
Alhough there is currently no gold-standard therapy for the treatment of fibromyalgia, a number of medications have shown modest efficacy in managing fibromyalgia-related pain, including
- milnacipran, and
However, these “do not necessarily provide a clinically meaningful improvement in FM-related pain for every patient,
perhaps due to their different mechanisms of action,” wrote the authors of the current study.
“Identifying treatment responders…can help refine treatment options and maximize patient outcomes while minimizing exposure to drugs for those patients who are less likely to respond.”
The present study, sponsored by Pfizer Inc, explored baseline patient characteristics that may have influenced these patients’ pain response to pregabalin compared with placebo. The mean pain score on an 11-point scale was the primary endpoint.
Pregabalin led to significant improvement in mean pain scores compared with placebo for most baseline characteristics, including age, fibromyalgia duration, depression diagnosis, depression < 10 years, prior opioid use, number of previous fibromyalgia medications, and severity of pain, anxiety, or sleep disruption (P <.05 for all).
However, patients with the following baseline characteristics or conditions did not demonstrate a significant response to pregabalin vs placebo:
- irritable bowel syndrome,
- gastroesophageal reflux disease,
- severe fibromyalgia (Fibromyalgia Impact Questionnaire with score rated on a 0 to 100 scale: total score, 59–100),
- depression diagnosis preceding fibromyalgia,
- depression ≥ 10 years,
- more severe depression (Hospital Anxiety and Depression Scale-Depression score ≥ 8), and
- high-dose antidepressant regimen.
These results are in line with those from earlier studies supporting pregabalin as an adequate therapy for pain in a broad population of patients with fibromyalgia.
Although the medication “did not improve pain severity in patients with severe [fibromyalgia] or more long-term or severe depression, it may be of value as part of a multimodal and multidisciplinary treatment regimen for these difficult-to-treat patients,” the researchers concluded.
Silverman SL, Backonja M, Pauer L, et al. Effect of baseline characteristics on the pain response to pregabalin in fibromyalgia patients with comorbid depression. Pain Med. 2017. doi:10.1093/pm/pnx091
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