Melatonin Unimedic Pharma (Melatonin)

Melatonin acts on melatonin receptors to address disorders of the sleep‑wake cycle.

• Insomnia: helps reduce sleep onset latency and improve sleep maintenance in individuals with difficulty falling or staying asleep.
• Jet lag: assists in realigning circadian rhythms after rapid east‑west travel, reducing daytime sleepiness and nighttime wakefulness.
• Sleep‑wake rhythm disorders: supports normalization of abnormal sleep patterns such as delayed sleep phase syndrome.

• Melatonin binds to MT1 and MT2 receptors in the suprachiasmatic nucleus of the hypothalamus, mimicking the endogenous hormone released by the pineal gland during darkness. Activation of these G‑protein‑coupled receptors modulates intracellular cyclic AMP levels, leading to phase‑shifting of the circadian clock and promotion of sleep onset. The agonist effect helps synchronize the internal biological rhythm with external light‑dark cycles.

Melatonin may cause a range of adverse reactions, varying from mild and transient to rare serious events that require medical attention.

Common Side Effects

• Drowsiness: feeling of sleepiness during daytime.
• Headache: mild to moderate head pain.
• Dizziness: sensation of light‑headedness or imbalance.
• Nausea: mild stomach upset.
• Vivid dreams: unusually intense or memorable dreams.
• Dry mouth: reduced saliva production.
• Abdominal cramps: mild stomach muscle pain.

Serious or Rare Side Effects

• Allergic reaction: rash, itching, swelling, or difficulty breathing.
• Mood changes: depression or increased anxiety.
• Hormonal effects: alterations in menstrual cycle or reproductive hormone levels.
• Severe hypotension: marked drop in blood pressure causing faintness.
• Paradoxical insomnia: worsening of sleep difficulty.
• Seizures: rare occurrence of convulsive episodes.
• Liver enzyme elevation: abnormal liver function tests.

When using melatonin, consider the following precautions to ensure safe and effective therapy.

• Assess underlying conditions: evaluate for depression, seizure disorders, or autoimmune disease before initiating therapy.
• Review concomitant medications: check for potential interactions with anticoagulants, immunosuppressants, or CNS depressants.
• Use the lowest effective dose: start with the smallest dose that improves sleep and adjust only under medical guidance.
• Avoid use in children without specialist advice: pediatric safety has not been fully established.
• Monitor for hormonal effects: observe menstrual irregularities or changes in reproductive hormone levels during prolonged use.
• Store below 25°C: keep in the original container, protect from moisture and direct sunlight.

Melatonin can interact with other medicines; interactions are categorized by their clinical significance.

Major Interactions (Avoid)

• Anticoagulants (e.g., warfarin): melatonin may enhance anticoagulant effect, increasing bleeding risk.
• Immunosuppressants (e.g., cyclosporine): possible alteration of drug levels leading to reduced efficacy.
• CNS depressants (e.g., benzodiazepines): additive sedative effect may cause excessive drowsiness.

Moderate Interactions (Monitor Closely)

• Oral contraceptives: melatonin may affect hormone metabolism, potentially reducing contraceptive effectiveness.
• Antidiabetic agents: melatonin can influence glucose control, requiring blood sugar monitoring.
• Antihypertensives: possible additive blood pressure lowering effect.
• Caffeine‑containing products: may counteract melatonin’s sleep‑promoting action.