Melatonin: Difference between revisions

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{{MedTemplate

| generic = Melatonin

| generic = Melatonin (N-acetyl-5-methoxytryptamine)

| brand =

| brand = Multiple OTC dietary supplement formulations

| structure =

| classes = ~~Sedative-Hypnotic, Oneirogen~~

| classes = [[:Category:Melatonin receptor agonists|Melatonin receptor agonist]], [[:Category:Sleep aids|Sleep aid]], [[:Category:Chronobiotics|Chronobiotic (circadian phase regulator)]]

| ~~mechanism =~~ Melatonin receptor agonist

| uses = <vote slug="sleep-onset-insomnia-melatonin-use">Sleep-onset insomnia (broad off-label use)</vote>, <vote slug="jet-lag-use">Jet lag (off-label, evidence-supported)</vote>, <vote slug="shift-work-disorder-use">Shift-work sleep-wake disorder (off-label)</vote>, <vote slug="delayed-sleep-phase-disorder-use">Delayed sleep phase syndrome (off-label, evidence-supported)</vote>, <vote slug="autism-pediatric-insomnia-use">Pediatric insomnia in autism spectrum disorder and ADHD (off-label, evidence-supported)</vote>, <vote slug="perioperative-anxiolysis-use">Perioperative anxiolysis (off-label)</vote>

| uses =

| starting_dose = 0.5-3 mg PO 30-60 minutes before bedtime. Some patients respond to micro-doses (0.3 mg) without additional benefit at higher doses. For circadian phase shifting, timing relative to dim-light melatonin onset matters more than absolute dose

| starting_dose =

| preparations = OTC tablets, sublingual tablets, gummies, liquid, extended-release tablets and capsules; common strengths 0.5, 1, 3, 5, 10 mg

| preparations =

| fda_max = Not formally established (dietary supplement); doses above ~3-5 mg show no additional efficacy but increase next-day sedation risk

| fda_max =

| pill_id =

| routes =

| routes = Oral, sublingual

| onset =

| onset = 30-60 minutes (immediate-release oral)

| duration =

| duration = 3-4 hours

| halflife =

| halflife = 30-50 minutes (short)<ref name="rozerem-label">FDA Prescribing Information, Rozerem (ramelteon), a closely-related selective MT1/MT2 receptor agonist; reference for melatonin receptor pharmacology. https://www.accessdata.fda.gov/drugsatfda_docs/label/2018/021782s016lbl.pdf</ref>

| bioavailability =

| bioavailability = ~15% (oral; highly variable due to extensive and variable first-pass metabolism)<ref name="rozerem-label" />

| pregnancy =

| pregnancy = Limited human data; endogenous hormone, but supplemental pharmacological doses are not well characterized in pregnancy.{{citation needed}}

| legal =

| legal = [[USLegal:Over-the-counter|OTC]] dietary supplement in the US ('''not FDA-regulated as a medicine'''; multiple studies show OTC products contain 50-470% of labeled melatonin content); [[USLegal:Prescription only|Rx-only]] in the EU and UK

| ~~intro =~~

| mechanism = <vote slug="melatonin-mech-claim">Endogenous hormone secreted by the pineal gland in response to darkness, agonist at MT1 receptors (mediating sleep-onset effect and suppression of the suprachiasmatic nucleus wakefulness signal) and MT2 receptors (mediating circadian phase regulation). Pharmacological dosing supplements the endogenous nighttime peak that is suppressed by evening light exposure, fragmented by aging, or misaligned in shift work, jet lag, and delayed sleep phase syndrome.</vote> Functions principally as a '''chronobiotic''' rather than a sedative-hypnotic in the benzodiazepine or non-benzodiazepine-hypnotic sense, with a modest sleep-onset effect that plateaus around 3 mg/day. Sustained-release and tasimelteon (Hetlioz) are MT-receptor-selective alternatives with regulated dosing<ref name="rozerem-label" />.

| ~~pharmacokinetics =~~

| ~~pharmacodynamics~~ =

~~| indications~~ =

| dosing =

~~| effects =~~

~~| interactions =~~ <~~pharmaInteractions~~/>

~~| pregnancy_details =~~

~~| monitoring =~~

~~| counseling =~~

~~| anecdotes =~~

~~| seealso =~~

~~| references~~ =

}}

== References ==

[[Category:~~Sedative-Hypnotics~~]]

[[Category:Sleep aids]]

[[Category:~~Dietary Precursors and Cofactors~~]]

[[Category:Melatonin receptor agonists]]

[[Category:~~Nootropics~~]]

[[Category:Chronobiotics]]

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