Melatonin Therapy for REM Sleep Behavior Disorder with Co-existing Moderate-to-Severe Sleep Apnea

ABSTRACT

BACKGROUND: REM sleep behavior disorder (RBD) commonly occurs in old-age group and shows very good response to clonazepam. However, clonazepam can aggravate or even precipitate sleep-disordered breathings (SDBs) that is highly prevalent among elderly people. Melatonin has been known to be effective in RBD treatment and is much less likely to increase the airway resistance. The aim is to document the efficacy of melatonin therapy in RBD with co-existing significant SDB. METHODS: We recruited consecutive patients who have both RBD and significant SDB (apnea-hypopnea index, AHI>15) confirmed by nocturnal polysomnography. Melatonin was started at the dose of 0.5 mg/night and increased according to the clinical response. Successful response is defined when symptoms are free or reduced in frequency more than 90% and any physical injury or violence should not be present. RESULTS: Eleven among 16 RBD patients were eligible and enrolled (eight male, median age 69 years, range 54-89). All had significant obstructive sleep-disordered breathings (mean AHI = 28.8, range 22.6-35.2). Melatonin was prescribed(dosage 2-8 mg/night, treatment duration, 7-35 months). Nine patients showed successful response (2-8 mg/night) but two showed unsatisfactory response to 6 mg or 8 mg/night. Two of nine patients with favorable response complained of mild sleepiness. CONCLUSIONS: Melatonin can be effective for controlling RBD with co-existing SDB. Effective dosage range is variable without intolerable adverse effect.