Pregabalin as add-on therapy induces REM sleep enhancement in partial epilepsy: a polysomnographic study

To evaluate the effects of pregabalin (PGB) adjunctive therapy on sleepwake cycle and daytime somnolence in adult patients affected by partial epilepsy. Twelve patients affected by partial epilepsy underwent a 24-h ambulatory polysomnography and a subjective evaluation of daytime somnolence by means of the Epworth Sleepiness Scale (ESS), before and after 3 months treatment with PGB. Pregabalin therapy reduced seizures by > 50% in 8 out of 12 patients. It induced a significant increase of REM sleep and a decrease of stage 2 NREM sleep (S2). A significant increase of the ESS score was observed without reaching the pathological cut-off value (mean ESS score < 10). No statistical correlation between REM sleep and seizure frequency was observed. Pregabalin seems to be effective and safe in partial epilepsy. The increase of REM sleep may be indicative of an improvement of nocturnal sleep quality considering the involvement of REM sleep in learning and memory processes. REM sleep enhancement may be the result of both a direct effect of PGB on sleep generators and an indirect effect due to its clinical efficacy. The increase of ESS score within normal range suggests that daytime somnolence is a minor adverse effect of PGB.