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Randomized Controlled Trial
. 2022 Sep;26(3):1023-1031.
doi: 10.1007/s11325-021-02417-w. Epub 2021 Aug 17.

Preliminary finding of a randomized, double-blind, placebo-controlled, crossover study to evaluate the safety and efficacy of 5-hydroxytryptophan on REM sleep behavior disorder in Parkinson's disease

Mario Meloni  1 , Michela Figorilli  2   3 , Manolo Carta  4 , Ludovica Tamburrino  2   3 , Antonino Cannas  3 , Fabrizio Sanna  4 , Giovanni Defazio  3 , Monica Puligheddu  5   6
Affiliations
Randomized Controlled Trial

Preliminary finding of a randomized, double-blind, placebo-controlled, crossover study to evaluate the safety and efficacy of 5-hydroxytryptophan on REM sleep behavior disorder in Parkinson's disease

Mario Meloni et al. Sleep Breath. 2022 Sep.

Abstract

Purpose: Altered serotonergic neurotransmission may contribute to the non-motor features commonly associated with Parkinson's disease (PD) such as sleep disorders. The 5-hydroxytryptophan (5-HTP) is the intermediate metabolite of L-tryptophan in the production of serotonin and melatonin. The purpose of this study was to compare the effects of 5-HTP to placebo on REM sleep behavior disorder (RBD) status in patients with PD.

Methods: A single-center, randomized, double-blind placebo-controlled crossover trial was performed in a selected population of 18 patients with PD and RBD. The patients received a placebo and 50 mg of 5-HTP daily in a crossover design over a period of 4 weeks.

Results: 5-HTP produced an increase in the total percentage of stage REM sleep without a related increase of RBD episodes, as well as a marginal, non-significant reduction in both arousal index and wake after sleep onset. The self-reported RBD frequency and clinical global impression (CGI) were improved during 5-HTP and placebo treatment in comparison to baseline. 5-HTP significantly improved our patients' motor experiences of daily living as rated by the Unified Parkinson's Disease Rating Scale (UPDRS) part II.

Conclusions: This study provides evidence that 5-HTP is safe and effective in improving sleep stability in PD, contributing to ameliorate patients' global sleep quality. Larger studies with higher doses and longer treatment duration are needed to corroborate these preliminary findings.

Keywords: 5-Hydroxytryptophan; Melatonin; Parkinson’s disease; REM sleep behavior disorder; Serotonin.

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Conflict of interest statement

The authors declare no competing interests.

Figures

Fig. 1
Fig. 1
Flowchart: enrollment, randomization, and retention of study participants
Fig. 2
Fig. 2
Polysomnographic sleep data: (secondaryoutcome)
Fig. 3
Fig. 3
Activities of daily living rated using the UnifiedParkinson Disease Rating Scale Part II (UPDRS II) (secondary outcome)
See this image and copyright information in PMC

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