Patients with fibromyalgia can safely be treated with the anticonvulsant drug pregabalin (Lyrica, Pfizer Inc) for their pain while at the same time being treated for depression, a new study shows.
Results of a double-blind study showed that pregabalin significantly improved mean pain scores compared with placebo in patients with fibromyalgia taking a selective serotonin reuptake inhibitor (SSRI) or a serotonin/norepinephrine reuptake inhibitor (SNRI).
Characterized by widespread musculoskeletal pain along with fatigue and sleep, memory, and mood problems, fibromyalgia is believed to affect the way the brain processes pain signals and is often accompanied by depression.
Pregabalin is an approved treatment for fibromyalgia, but previous clinical trials required patients to discontinue antidepressant treatment.
The new study results were presented here during PAINWeek by Richard Vissing, PharmD, senior director, field medical director, pain, North American Medical Affairs, Global Innovative Pharma Business, Pfizer Inc, Louisville, Kentucky. This study, supported by Pfizer Inc, was 1 of only 6 selected for a special poster presentation during the meeting.
The analysis included 193 patients with fibromyalgia age 18 years and older at 38 centers in the United States, Canada, Italy, and Spain. Most (93.3%) were female and white (93.8%), and their mean age was 50.1 years.
The participants had to have a documented diagnosis of depression and to have been taking a stable SSRI or SNRI to treat depression, not pain, for the previous 2 months. About half of the patients were receiving an SSRI and the other half an SNRI. At study onset, they had a mean pain score of 4 or more on a numeric rating scale where 0 indicates no pain and 10 the worst pain.
Patients were randomly assigned to placebo or pregabalin (150 to 450 mg/day) for 6 weeks and then crossed over to the other treatment for another 6 weeks, with a 2-week taper/washout in between. Patients continued to take their antidepressants for the duration of the trial.
Interestingly, Dr. Vissing noted that discontinuation rates were “very similar” for the 2 groups: 12.2% for those taking pregabalin and 12.4% for those receiving placebo.
Results showed that mean pain scores were significantly lower for pregabalin recipients than for placebo recipients (4.84 vs 5.45; difference, –0.61; 95% confidence interval, –0.91 to –0.31; P = .0001).
“The treatment differences were apparent as early as the first week of treatment and were maintained for the duration of the study,” said Dr. Vissing. “And it didn’t matter patients were taking an SSRI or an SNRI.”
Pregabalin treatment was also significantly better than placebo on many secondary endpoints, including the number of patients with a 30% or greater and 50% or greater reduction in mean pain scores and scores for depression and anxiety (A and D) on the Hospital Anxiety and Depression Scale (HADS).
“We saw an improvement in HADS-D, but I think more importantly, you got these patients who were coming through who were on a stable antidepressant and we didn’t worsen their depression,” he said. “They didn’t have to change their medication, so from a safety perspective, I think that’s important to know.”
Patients taking pregabalin also did better in terms of function as tested on the Fibromyalgia Impact Questionnaire (difference in score, –6.60; P < .0001) and on several sleep measures, including sleep quality.
Adverse events were reported in 77.3% of those taking pregabalin and 59.9% of those receiving placebo. The most common adverse events were dizziness and somnolence. This, said Dr. Vissing, is consistent with previous studies of pregabalin.
Co-chair of the poster session, Joseph Pergolizzi Jr, MD, assistant professor, medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, commented on the unique design of the study. As previous clinical trials required patients with fibromyalgia to discontinue antidepressant medication, the question of whether this population could be safety and effectively treated with pregabalin while taking antidepressants for comorbid depression was left open.
“So many fibromyalgia patients have comorbidity of depression and there is a general concern that pregabalin might worsen depression,” said Dr. Vissing. “This study provided evidence that it did not. Many fibro patients are on multiple drugs, including antidepressants and pain meds, so it appears that concomitant use is safe and effective.”