Gabapentin enacarbil significantly improved symptoms in severe primary restless leg syndrome, according to research published in Sleep Medicine.

In a study conducted by Daniel Lee, MD, from Baptist Health Neurology in Richmond, Kentucky and colleagues, the researchers found that both 600 mg and 1200 mg of gabapentin enacarbil (GEn) administered once daily to patients with severe primary restless leg syndrome (RLS) significantly improved sleep, mood, pain, and quality of life compared with placebo. Participants who took GEn 1200 mg generally had greater improvements in their symptoms.

“Treatment effects compared with placebo were generally numerically greater for GEn 1200 mg than for GEn 600 mg,” the authors wrote. “However, caution should be exercised when interpreting these data for clinical practice purposes, as only GEn 600 mg is currently approved by the FDA for the treatment of moderate-to-severe primary RLS.”

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For the study, the researchers included 309 participants with severe primary RLS. Eighty participants received GEn 600 mg, 119 participants received GEn 1200 mg, and 110 participants received a placebo. Significantly more participants treated with GEn 600 mg (64%) and GEn 1200 mg (74%) were either “much” or “very much” improved on the investigator-rated Clinical Global Impression—Improvement (CGI-I) scale at 12 weeks vs placebo (42%; p<0.01 for both GEn doses).

The most frequent adverse effects were drowsiness (GEn, 21–24%; placebo, 3%) and dizziness (GEn, 14–19%; placebo, 3%).

“As the first pooled analysis of adult patients with severe primary RLS treated with GEn, these data show that the benefits of GEn extend to patients who experience the most pronounced RLS symptoms,” the authors wrote. “Future studies are recommended to further explore and evaluate GEn efficacy outcomes specifically in adult patients with severe primary RLS.”


Lee DO, Buchfuhrer MJ, Garcia-Borreguero D, et al. Efficacy of gabapentin enacarbil in adult patients with severe primary restless legs syndrome. Sleep Med. 2015; doi:10.1016/j.sleep.2015.11.002.