Melatonin

• Melatonin is a melatonin receptor agonist used to address sleep‑related disorders.
• Insomnia: improves sleep onset and maintenance in adults with difficulty falling or staying asleep.
• Jet lag: assists in realigning the circadian rhythm after rapid east‑west travel.
• Circadian rhythm sleep disorder: supports sleep regulation in shift‑work or delayed sleep phase syndrome.

• Melatonin acts as an agonist at the MT1 and MT2 receptors in the suprachiasmatic nucleus of the hypothalamus. Activation of these receptors synchronizes the endogenous circadian clock, reduces neuronal firing during the night, and facilitates the onset of sleep by mimicking the body’s natural melatonin surge.

Melatonin is generally well tolerated, but adverse reactions can occur.

Common Side Effects

• Drowsiness or daytime sleepiness
• Headache
• Dizziness
• Nausea or mild gastrointestinal discomfort
• Vivid dreams or nightmares
• Mild fatigue

Serious or Rare Side Effects

• Allergic reactions such as rash, itching, or swelling
• Severe daytime somnolence affecting alertness
• Mood changes including depression or anxiety
• Hallucinations or confusion (rare)
• Abnormal heart rhythm or palpitations (very rare)

• When using melatonin, consider the following precautions.
• Assess sleep disorder before initiating therapy: confirm diagnosis and suitability.
• Avoid operating machinery or driving if drowsy: monitor for impaired alertness.
• Use with caution in hepatic impairment: metabolism may be altered.
• Not recommended for children unless prescribed by a specialist.
• Avoid concurrent use with other sedatives without medical advice.
• Store at room temperature: keep in the original pack, protect from moisture.

Melatonin may interact with other medications; monitor accordingly.

Major Interactions (Avoid)

• Concurrent use with benzodiazepines or other sedative hypnotics: risk of excessive sedation.
• Co‑administration with anticoagulants (e.g., warfarin): possible increased bleeding risk.

Moderate Interactions (Monitor Closely)

• Antidepressants (SSRIs, SNRIs): may alter melatonin metabolism.
• Oral contraceptives: can increase melatonin plasma levels.
• Anticonvulsants (e.g., carbamazepine): may reduce melatonin effectiveness.
• Caffeine-containing products: may diminish sleep‑promoting effect.
• NSAIDs: may increase risk of gastrointestinal upset.