Abnormal melatonin secretion and circadian rhythmicity are thought to contribute to altered sleep–wake cycles in children with autism and other neurodevelopmental disorders. Slenyto is a prolonged-release minitablet formulation of melatonin designed to be acceptable to children with swallowing difficulties, which are common in autism.
The efficacy and safety of prolonged-release melatonin were assessed in a randomised, placebo-controlled study in children with autism spectrum disorders or neurodevelopmental disabilities caused by Smith-Magenis syndrome who had not shown improvement in insomnia after standard behavioural intervention.
A total of 125 children (97% with autism spectrum disorders; 3% with Smith-Magenis syndrome) were randomised. After 13 weeks of double-blind treatment, those treated with prolonged-release melatonin achieved an additional 57.5 minutes sleep each night on average, compared to an additional 9.14 minutes for those given placebo (p=0.034). Compliance with tablet-taking was 100%.
The beneficial effects of melatonin were maintained in a 39-week extension study which included 95 of the original participants. In addition, 49% of caregivers experienced a meaningful improvement in their own quality of life at week 39.
Of the 26 adverse events in the extension study that were considered related to the study medication, the most commonly reported were fatigue (5.3%); mood swings (3.2%); irritability, aggression, hangover and somnolence (2.1% each).