Melatonin Orion Pharma (Melatonin)

Melatonin acts on melatonin receptors to adjust circadian timing and is employed for several sleep‑related conditions.

• Insomnia: helps reduce sleep onset latency and improve sleep quality in individuals with difficulty falling asleep.
• Jet lag: assists in realigning the internal clock after rapid east‑west travel, facilitating faster adaptation to new time zones.
• Shift work disorder: supports workers with irregular schedules to achieve more consistent sleep patterns.

• Melatonin binds to MT1 and MT2 receptors in the suprachiasmatic nucleus of the hypothalamus, mimicking the endogenous hormone released during darkness. Activation of these G‑protein‑coupled receptors modulates intracellular cyclic AMP levels, leading to phase‑shifting of the circadian pacemaker and promotion of sleep propensity. By enhancing receptor signaling, melatonin helps synchronize the body's internal clock with external light‑dark cycles. The effect is dose‑dependent and most pronounced when administered in the evening before bedtime.

Melatonin is generally well tolerated, but some users may experience adverse reactions.

Common Side Effects

• Drowsiness: feeling of increased sleepiness during the day.
• Headache: mild to moderate head pain.
• Dizziness: sensation of light‑headedness or imbalance.
• Nausea: mild stomach upset.
• Vivid dreams: unusually intense or memorable dreams.
• Fatigue: general lack of energy.

Serious or Rare Side Effects

• Allergic reaction: rash, itching, swelling, or hives.
• Severe hypotension: marked drop in blood pressure.
• Mood changes: depression or increased anxiety.
• Seizures: rare occurrence of convulsive episodes.
• Hallucinations: visual or auditory disturbances.

When considering melatonin therapy, several precautionary measures should be observed to ensure safe use.

• Medical supervision: use under guidance of a healthcare professional, especially for children or chronic use.
• Hypersensitivity: avoid if known allergy to melatonin or excipients.
• Anticoagulant use: monitor bleeding risk when combined with warfarin or similar agents.
• Depression history: use cautiously in patients with depressive disorders.
• Pregnancy and lactation: safety not established; discuss risks with a physician.
• Store at ambient temperature below 25°C: keep in the original container, protect from moisture and light.

Melatonin can interact with other medicines, altering their effectiveness or safety profile.

Major Interactions (Avoid)

• Anticoagulants (e.g., warfarin): increased bleeding risk.
• Immunosuppressants (e.g., cyclosporine): reduced drug levels.
• Central nervous system depressants (e.g., benzodiazepines): excessive sedation.

Moderate Interactions (Monitor Closely)

• Oral contraceptives: possible reduction in contraceptive efficacy.
• Antihypertensives: additive blood pressure‑lowering effect.
• Antidiabetic agents: potential alteration of glucose control.
• Caffeine: may diminish melatonin’s sleep‑inducing effect.