Assessing Adverse Events in Pregabalin Use and Fibromyalgia

October 18, 2009
Bradley Schmidt

Despite findings from other studies indicating that somnolence is a sometimes significant adverse effect in pregabalin use, this study suggests that it is statistically insignificant.

Studies have demonstrated the efficacy of pregabalin in relieving fibromyalgia symptoms, however, in some studies, somnolence has been reported in 18 to 28 percent of patients with fibromyalgia compared with 3.8 to 6 percent of patients treated with placebo.

This, according to Lynne Pauer of Pfizer Global Research & Development, creates “the perception that the adverse event of somnolence could be driving efficacy observed with pregabalin.” This necessitated the study which evaluated “whether somnolence influenced the treatment response to pregabalin in patients with fibromayalgia by comparing pain, function, and sleep outcomes between patients.”

Researchers summarized data from three fibromyalgia studies each 12 weeks in length, pooled the data, and stratified patients by whether or not they had reported an adverse event of somnolence. Of “2,227 patients included in the analysis, 366…reported somnolence at any time during the study and 1,861 who did not report somnolence,” a statistically insignificant figure.

“It’s important for us to know that this adverse event is not what’s driving efficacy,” says Pauer, who isn’t sure about its implications for new research efforts. “We’ll continue to assess patients for these adverse events for somnolence and we’ll continue to assess our data in the same manner, but we just wanted to find out and be able to suggest that there’s something else that’s driving our treatment. I don’t know that if the research will take a different direction but it’s just important for us to establish this.”