Adult: As conventional cap or oral solution: 1-5 mg once daily for 5 days; may increase up to 6 mg daily if necessary. Doses are given between 8 PM and 4 AM (preferably before midnight) at the destination and given 2 hours before or 2 hours after meals. Max: 16 treatment periods per year.
Oral Short-term management of insomnia
Adult: Primary cases: As prolonged-release tab: ≥55 years 2 mg once daily, given 1-2 hours before bedtime and after food. Doses may be given for up to 13 weeks.
Oral Sleep-onset insomnia
Child: In patients with attention deficit hyperactivity disorder (ADHD) when sleep hygiene measures are inadequate: As oral solution: 6-17 years Initially, 1-2 mg 30-60 minutes before bedtime; may increase by 1 mg weekly up to a Max of 5 mg daily if necessary. Doses are given 2 hours before or 2 hours after meals.
Hepatic Impairment
Short-term management of jet lag; Short-term management of insomnia:
As prolonged-release tab: Not recommended. As conventional cap or oral solution: Moderate to severe: Not recommended.
Administration
Melatonin May be taken with or without food. Recommendations on taking w/ or w/o food are product-specific. Consult product literature for specific instructions.
Special Precautions
Patient with seizures, multiple neurological defects, autoimmune disease. Smokers. Melatonin is available in different formulations, which are not equivalent; dose adjustment and monitoring may be necessary when switching between dosage forms. Renal and hepatic impairment. Children. Pregnancy and lactation.
Adverse Reactions
Significant: CNS depression, drowsiness; increased seizure frequency; exacerbation of autoimmune disease. Cardiac disorders: Chest pain. Gastrointestinal disorders: Nausea, dry mouth, oral ulcers, abdominal pain, dyspepsia. General disorders and administration site conditions: Asthenia. Hepatobiliary disorders: Hyperbilirubinaemia. Investigations: Increased weight, abnormal LFTs. Musculoskeletal and connective tissue disorders: Malaise, pain in extremity. Nervous system disorders: Headache, somnolence, dizziness, migraine, lethargy, psychomotor hyperactivity. Psychiatric disorders: Irritability, nervousness, restlessness, abnormal dreams, anxiety. Renal and urinary disorders: Glycosuria, proteinuria. Reproductive system and breast disorders: Menopausal symptoms. Skin and subcutaneous tissue disorders: Rash, dry skin, pruritus, dermatitis, night sweats. Vascular disorders: Hypertension.
Patient Counseling Information
This drug may cause drowsiness and decreased alertness, if affected, do not drive or operate machinery.
Monitoring Parameters
Monitor sleep improvement.
Overdosage
Symptoms: Drowsiness, headache, dizziness, nausea, flushes, abdominal cramps, diarrhoea, and scotoma lucidum. Management: Symptomatic and supportive treatment. May consider gastric lavage and activated charcoal administration.
Drug Interactions
Increased plasma concentrations with fluvoxamine, 5-methoxypsoralen, methoxsalen, cimetidine, estrogen or other estrogen-containing agents, and CPY1A2 inhibitors (e.g. quinolones). Decreased plasma concentrations with CYP1A2 inducers (e.g. carbamazepine, rifampicin). May enhance the sedative effect of benzodiazepines (e.g. midazolam, temazepam) and non-benzodiazepine hypnotics (e.g. zaleplon, zolpidem, zopiclone). May alter the anticoagulation effect of warfarin. Increased risk of seizures with drugs that increases seizure frequency. May reduce the antihypertensive effect of calcium channel blockers.
Food Interaction
Delayed absorption and decreased peak plasma concentration with food. Decreased therapeutic effect with alcohol.
Action
Description: Mechanism of Action: Melatonin is a hormone secreted by the pineal gland. Its agonist activity at the MT1, MT2, and MT3 receptors is believed to contribute to its sleep-promoting properties, as these receptors, particularly MT1 and MT2, are involved in circadian rhythm and sleep regulation. Pharmacokinetics: Absorption: Completely absorbed. Delayed absorption and decreased peak plasma concentration with food. Bioavailability: Approx 15%. Time to peak plasma concentration: Conventional form: Approx 50 minutes; prolonged-release: 2.6-3 hours (fed); 0.75-1.6 hours (fasting). Distribution: Crosses the placenta and enters breast milk. Plasma protein binding: Approx 50-60% (mainly to albumin, α1-acid glycoprotein, HDL). Metabolism: Metabolised in the liver by CYP1A1, CYP1A2 and CYP2C19 into 6-sulphatoxy-melatonin (inactive metabolite). Undergoes first-pass metabolism. Excretion: Via urine (89% as inactive metabolites; 2% as unchanged drug). Elimination half-life: Approx 45 minutes (conventional form); 3.5-4 hours (prolonged-release).
Chemical Structure
Melatonin Source: National Center for Biotechnology Information. PubChem Compound Summary for CID 896, Melatonin. https://pubchem.ncbi.nlm.nih.gov/compound/Melatonin. Accessed Aug. 26, 2025.
Sign Out
Continue with Google