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Reply to letter: Exogenous melatonin for Parkinson’s disease: ‘Waking up’ to the need for further trials

2016; Elsevier BV; Volume: 29; Linguagem: Inglês

10.1016/j.parkreldis.2016.05.011

1873-5126

Tiago M. Rodrigues, Ana Castro Caldas, Joaquim J. Ferreira,

Sleep and related disorders

We would like to thank Dr. Breen and Professor Barker for their interest and insightful comments on our recently published systematic review and meta-analysis about the pharmacological management of excessive daytime somnolence and sleep disorders in Parkinson's disease (PD) [ [1] Rodrigues T.M. Castro Caldas A. Ferreira J.J. Pharmacological interventions for daytime sleepiness and sleep disorders in Parkinson's Disease: systematic review and meta-analysis. Park. Relat. Disord. 2016; 27: 25-34 Abstract Full Text Full Text PDF Scopus (66) Google Scholar ]. Indeed, data from animal models and clinical studies suggest that circadian rhythms are disrupted in PD, namely the sleep/wake cycle, putatively due to PD-related neurodegeneration of central sleep regulatory areas and to adverse effects of antiparkinsonian drugs. The rationale for using melatonin as a therapeutic strategy stems from this observation. However, it should be noted that most clinical studies assessing the circadian secretion of melatonin in PD patients showed no significant differences in circadian phase relative to healthy controls, but have produced controversial results regarding secretion amplitude (for review, see Ref. [ [2] Videnovic A. Willis G.L. Circadian system – a novel diagnostic and therapeutic target in Parkinson's disease?. Mov. Disord. 2016; 31: 260-269 Crossref Scopus (72) Google Scholar ]). Exogenous melatonin for Parkinson's disease: 'Waking up' to the need for further trialsParkinsonism & Related DisordersVol. 29PreviewWe enjoyed the recent systematic review from Rodrigues and colleagues which evaluated the efficacy and safety of pharmacological interventions for daytime sleepiness and sleep disorders in Parkinson's disease (PD) [1]. Their search strategy yielded only one randomised controlled trial relating to melatonin. Dowling et al. reported that melatonin 50mg daily, taken 30 minutes before bedtime, led to a small but statistically significant increase in nightime sleep time (measured using actigraphy), whilst melatonin 5mg daily improved subjective sleep quality and daytime sleepiness [2]. Full-Text PDF