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Melatonin as a medication and supplement

Medical Uses and Applications: – Melatonin is useful in treating delayed sleep phase syndrome. – It can reduce jet lag, especially in eastward travel. – […]

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Medical Uses and Applications:
– Melatonin is useful in treating delayed sleep phase syndrome.
– It can reduce jet lag, especially in eastward travel.
– Limited use against sleep problems of shift workers.
– Tentative evidence suggests it increases sleep duration.
– Safer alternative to clonazepam for REM sleep behavior disorder.
– Prolonged-release Circadin approved for insomnia in the EU.
– Over-the-counter dietary supplement in many countries.
– Immediate and prolonged-release forms available.
– Doses range from 0.3mg to 10mg or more.
– Available in various oral formulations and transdermal patches.

Safety and Adverse Effects:
– Few side effects at low doses for up to 3 months.
– Prolonged-release melatonin safe for up to 12 months.
– Low-dose melatonin safer than many sleep aids.
– Higher doses do not increase efficacy.
– Timing of melatonin intake in relation to food is crucial.
– Melatonin is relatively safe in overdose.
– Adverse effects of overdose include somnolence.
– No special treatment is needed for melatonin overdose.

Pharmacology and Chemistry:
– Melatonin acts as an agonist of the melatonin MT and MT receptors.
– Endogenous melatonin is secreted from the pineal gland of the brain.
– Melatonin activates melatonin receptors in the hypothalamus to regulate circadian clock and sleep-wake cycles.
– Melatonin is a substituted tryptamine, a derivative of serotonin.
– Synthetic melatonin receptor agonists like ramelteon are analogues of melatonin.
– Piromelatine, an analogue of melatonin, is still in clinical trials.

Research Studies and Reviews:
– Various studies have been conducted on melatonin for different conditions.
– Reviews have explored its efficacy and safety in different medical contexts.
– Studies have focused on specific disorders like dementia, epilepsy, and cancer.
– Meta-analyses have been done on melatonin’s impact on sleep disorders.
– Comprehensive reviews have discussed melatonin’s role in various health outcomes.

Interactions, History, and Miscellaneous Uses:
– Melatonin metabolism can be influenced by CYP1A enzymes.
– Interactions with medications like fluvoxamine and warfarin have been noted.
– Melatonin gained attention for various illnesses in the late 20th century.
– Melatonin was approved for medical use in the European Union in 2007.
– Melatonin has been studied for headaches, cancer, radiation protection, epilepsy, and other conditions.
– Limited evidence exists for melatonin’s efficacy in some conditions like dysmenorrhea and delirium.

Melatonin as a medication and supplement (Wikipedia)

Melatonin is a dietary supplement and medication as well as naturally occurring hormone. As a hormone, melatonin is released by the pineal gland and is involved in sleep–wake cycles. As a supplement, it is often used for the attempted short-term treatment of disrupted sleep patterns, such as from jet lag or shift work, and is typically taken orally. Evidence of its benefit for this use, however, is not strong. A 2017 review found that sleep onset occurred six minutes faster with use, but found no change in total time asleep.

Clinical data
Trade namesCircadin, Slenyto, others
Other namesN-Acetyl-5-methoxy tryptamine
AHFS/Drugs.comConsumer Drug Information
License data
  • AU: B3
Physical: Low Psychological: Low
Low / none
Routes of
By mouth, sublingual, transdermal
Drug classMelatonin receptor agonist
ATC code
Physiological data
Source tissuesPineal gland
Target tissuesWidespread, including brain, retina, and circulatory system
ReceptorsMelatonin receptor
MetabolismLiver via CYP1A2 mediated 6-hydroxylation
Legal status
Legal status
  • AU: S4 (Prescription only)
  • CA: OTC
  • UK: POM (Prescription only)
  • US: OTC
  • EU: Rx, OTC
  • In general: ℞ (Prescription only)
Pharmacokinetic data
Protein binding60%
MetabolismLiver via CYP1A2 mediated 6-hydroxylation
Metabolites6-Hydroxymelatonin, N-acetyl-5-hydroxytryptamine, 5-methoxytryptamine
Elimination half-lifeIR: 20–60 minutes
PR: 3.5–4 hours
  • N-[2-(5-Methoxy-1H-indol-3-yl)ethyl]acetamide
CAS Number
PubChem CID
Chemical and physical data
Molar mass232.283 g·mol−1
3D model (JSmol)
Melting point117 °C (243 °F)
  • COC1=CC2=C(NC=C2CCNC(C)=O)C=C1
  • InChI=1S/C13H16N2O2/c1-9(16)14-6-5-10-8-15-13-4-3-11(17-2)7-12(10)13/h3-4,7-8,15H,5-6H2,1-2H3,(H,14,16) checkY

Side effects from melatonin supplements are minimal at low doses for short durations (in the studies reported about equally for both melatonin and placebo). Side effects of melatonin are rare but may occur in 1 to 10 patients in 1,000. They may include somnolence (sleepiness), headaches, nausea, diarrhea, abnormal dreams, irritability, nervousness, restlessness, insomnia, anxiety, migraine, lethargy, psychomotor hyperactivity, dizziness, hypertension, abdominal pain, heartburn, mouth ulcers, dry mouth, hyperbilirubinaemia, dermatitis, night sweats, pruritus, rash, dry skin, pain in the extremities, symptoms of menopause, chest pain, glycosuria (sugar in the urine), proteinuria (protein in the urine), abnormal liver function tests, increased weight, tiredness, mood swings, aggression and feeling hungover. Its use is not recommended during pregnancy or breastfeeding or for those with liver disease.

Melatonin acts as an agonist of the melatonin MT1 and MT2 receptors, the biological targets of endogenous melatonin. It is thought to activate these receptors in the suprachiasmatic nucleus of the hypothalamus in the brain to regulate the circadian clock and sleep–wake cycles. Immediate-release melatonin has a short elimination half-life of about 20 to 50 minutes. Prolonged-release melatonin used as a medication has a half-life of 3.5 to 4 hours.

Melatonin was discovered in 1958. It is sold over the counter in Canada and the United States; in the United Kingdom, it is a prescription-only medication. In Australia and the European Union, it is indicated for difficulty sleeping in people over the age of 54. In the European Union, it is indicated for the treatment of insomnia in children and adolescents. The US Food and Drug Administration (FDA) treats melatonin as a dietary supplement and as such has not approved it for any medical uses. It was approved for medical use in the European Union in 2007. Besides melatonin, certain synthetic melatonin receptor agonists like ramelteon, tasimelteon, and agomelatine are also used in medicine. In 2021, it was the 257th most commonly prescribed medication in the United States, with more than 1 million prescriptions.

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