ramelteon
Brand: Rozerem
Prototype Drug
Drug Class: melatonin receptor agonist
Drug Family: sedative/hypnotic
Subclass: MT1/MT2 receptor agonist hypnotic
Organ Systems: cns
Mechanism of Action
Highly selective agonist of MT1 and MT2 melatonin receptors in the suprachiasmatic nucleus (SCN), the brain's circadian pacemaker. Activation of MT1 inhibits the firing rate of SCN neurons (sleep-promoting), while MT2 activation shifts the circadian clock phase. Does not act on GABA-A receptors; no dependence potential.
melatonin MT1 and MT2 receptors (suprachiasmatic nucleus)
Indications
- insomnia characterized by difficulty with sleep onset
- jet lag / circadian rhythm disruption
Contraindications
- severe hepatic impairment (fluvoxamine interaction — contraindicated)
- concurrent fluvoxamine
Adverse Effects
Common
- somnolence
- fatigue
- dizziness
- nausea
Serious
- complex sleep behaviors (rare; class effect of any hypnotic?)
- prolactin elevation (testosterone reduction — monitor reproductive hormones)
- worsening depression or suicidal ideation (rare)
Pharmacokinetics (ADME)
| Absorption | oral; bioavailability ~1.8% (extensive first-pass metabolism); take on empty stomach |
| Distribution | 82% protein bound |
| Metabolism | hepatic via CYP1A2 (major) and CYP3A4, CYP2C9 |
| Excretion | renal (84%) |
| Half-life | 1–2.6 hours |
| Onset | 30 minutes |
| Peak | 0.75 hours |
| Duration | 3–4 hours |
| Protein Binding | 82% |
| Vd | 73.6 L |
Drug Interactions
| Drug / Agent | Mechanism | Severity |
|---|---|---|
| fluvoxamine | potent CYP1A2 inhibitor; increases ramelteon AUC 190-fold; CONTRAINDICATED | contraindicated |
| rifampin | CYP induction reduces ramelteon levels significantly | major |
Nursing Considerations
- Administer 30 minutes before bedtime on an empty stomach (food reduces absorption).
- Safe for use in elderly without fall risk concerns (no benzodiazepine mechanism).
- Not a controlled substance — no dependence, no withdrawal, no rebound insomnia on discontinuation.
- Monitor prolactin and testosterone levels in patients using ramelteon long-term; elevated prolactin and decreased testosterone have been reported.
Clinical Pearls
- Ramelteon is the only FDA-approved insomnia agent without Schedule IV or abuse potential; it is not a controlled substance, making it uniquely appropriate for patients with substance use disorders.
- The fluvoxamine-ramelteon interaction is one of the most extreme CYP1A2 inhibition examples: a 190-fold increase in AUC that represents a true absolute contraindication.
Safety Profile
Pregnancy avoid
Lactation insufficient-data
Renal Adjustment Not required
Hepatic Adjustment Required
TDM Not required
Concordance Terms
Cross-referenced clinical concepts — click any term to see all content where it appears.