Key points from the evidence
The content of this evidence summary was up-to-date in January 2013. See summaries of product characteristics (SPCs), British national formulary (BNF), BNF for children (BNFc) or the MHRA or NICE websites for up-to-date information.
Melatonin is a naturally occurring hormone produced by the pineal gland in the brain. It is involved in coordinating the body's sleep-wake cycle and helping to regulate sleep.
Only 1 form of melatonin (prolonged-release tablets) is currently licensed in the UK for the short-term treatment of primary insomnia, characterised by poor quality of sleep, in adults who are aged 55 years or over. Additional melatonin products are available from special-order manufacturers or specialist importing companies, or can be purchased directly online.
No high-quality studies were identified that provided evidence for the efficacy of prolonged-release melatonin tablets (licensed in the UK) used off-label in children with sleep disorders and attention deficit hyperactivity disorder (ADHD).
Limited evidence for unlicensed melatonin products was identified from 2 small (n=105 and 19) short-term randomised controlled trials (RCTs) and 1 small, long-term follow-up study (n=94). The evidence suggests that unlicensed melatonin products, taken for 10 days to 4 weeks, may reduce sleep onset latency (the time taken for a child to go to sleep) in children with sleep onset insomnia and ADHD by approximately 20 minutes. In addition melatonin may improve average sleep duration by 15 to 20 minutes. However, there are limitations to these small studies, and longer term efficacy is unclear.
These RCTs included stimulant and non-stimulant treated children aged 6 to 14 years with ADHD and suffering from sleep onset insomnia. The studies used daily doses of between 3 and 6 mg of unlicensed melatonin described as 'fast-release' or 'short-acting', administered shortly before bedtime.
Associated improvement in ADHD-related behaviour, cognition or quality of life was not robustly demonstrated.
Unlicensed melatonin used in the RCTs appeared well tolerated in the short to medium term with only transient mild to moderate adverse effects reported.
About this evidence summary
'Evidence summaries: unlicensed or off-label medicines' summarise the published evidence for selected unlicensed or off-label medicines that are considered to be of significance to the NHS, where there are no clinically appropriate licensed alternatives. The summaries provide information for clinicians and patients to inform their decision-making and support the construction and updating of local formularies.
The summaries support decision-making on the use of an unlicensed or off-label medicine for an individual patient, where there are good clinical reasons for its use, usually when there is no licensed medicine for the condition requiring treatment, or the licensed medicine is not appropriate for that individual.
The strengths and weaknesses of the relevant evidence are critically reviewed within this summary, but this summary is not NICE guidance.