Pharmacological treatment for REM sleep behavior disorder in Parkinson disease and related conditions: A scoping review

Rapid eye movement (REM) sleep behavior disorder (RBD) is a parasomnia characterized by the presence of a complex of signals resulting from the loss of REM sleep atony and manifested by vigorous and sometimes violent motor jerks and nocturnal vocalizations associated with dream enactment. RBD might be a clinical predictor of severity for Parkinson's disease (PD) and one of its most important non-motor manifestations, preceding the emergence of synucleinopathy by several years or even decades. The detection of RBD may represent a therapeutic window for research regarding the development of new neuroprotective therapies with the potential to modify the natural course of synucleinopathies, such as PD. We performed a scoping review of studies indexed in MEDLINE and LILACS focusing on pharmacological interventions for RBD associated with PD. Fourteen articles were selected. Study designs comprised randomized and non-randomized clinical trials (n = 153 participants) and observational studies (retrospective cohorts and case series, n = 248 participants). Melatonin and clonazepam appear to be useful for treating RBD in PD, but these findings are mostly supported by observational studies and a few controlled studies with a small number of participants. New pharmacological agents, such as melatoninergic agonists and phytocannabinoids, appear to be promising therapies. The findings from studies focusing on anticholinesterases and new dopaminergic agents are still deemed inconclusive.