Products
Melatonin receptor agonists are commercially available in tablet and capsule form.
Structure and properties
Melatonin receptor agonists are structurally derived from and related to the natural hormone melatonin.
Effects
Melatonin, a sleep hormone produced by the pineal (pineal) gland of the brain from tryptophan, has a central role in the body in regulating the sleep-wake cycle (circadian rhythm). It has sleep-promoting properties and reduces body temperature. Physiologically, melatonin levels in the blood rise after nightfall, reach their peak towards the middle of the night and develop their sleep-promoting effect. Light is the hormone’s main natural antagonist. The effects are based on binding to melatonin (MT) receptors. Melatonin receptor agonists have sleep-promoting properties. As with the natural hormone, the effects are based on binding to melatonin receptors, predominantly MT1 and MT2. Agomelatine (Valdoxan) additionally blocks serotonin 5-HT2C receptors and therefore has antidepressant effects.
Active Substances
- Agomelatine (Valdoxan)
- Ramelteon (Rozerem)
- Tasimelteon (Hetlioz)
Natural Ligand:
- Melatonin (e.g. Circadin).
Indications
- Sleep disorders, difficulty falling asleep
- Depressive episodes
- Non-24-Hour Sleep-Wake Disorder (Non-24)
Other indications (no approval yet):
- Jet lag
- Shift work
- Other disturbances of the sleep-wake rhythm
Dosage
According to the SmPC. Melatonin receptor agonists are usually taken once daily in the evening before bedtime.
Contraindications
Contraindications include:
- Hypersensitivity
- Combination with CYP1A inhibitors such as fluvoxamine.
- Impaired liver function (agomelatine).
For complete precautions, see the drug label.
Interactions
Melatonin receptor agonists are substrates of CYP450 and CYP1A in particular. Corresponding drug-drug interactions are possible. Central depressant drugs and alcohol may potentiate adverse effects.
Adverse effects
Possible adverse effects include headache, dizziness, unusual dreams, indigestion, drowsiness, fatigue, and gastrointestinal disturbances. The drugs may cause drowsiness and therefore should not be taken when increased concentration is required, such as when driving.
