RAMELTEON
Clinical safety rating: caution
Comprehensive clinical and safety monograph for RAMELTEON (RAMELTEON).
Selective melatonin receptor agonist with high affinity for MT1 and MT2 receptors in the suprachiasmatic nucleus; promotes sleep by mimicking the effects of endogenous melatonin.
| Metabolism | Hepatic via CYP1A2 (major), CYP2C9, and CYP3A4; first-pass metabolism extensive; major metabolite M-II (active but less potent). |
| Excretion | Ramelteon is extensively metabolized, primarily via CYP1A2 and to a lesser extent CYP2C9 and CYP3A4. Approximately 84% of the dose is excreted in urine as metabolites, with 4% as unchanged drug. Fecal excretion accounts for about 4% of the dose. |
| Half-life | 1-2.6 hours. The terminal half-life is short (mean ~1.3 hours) with no accumulation upon repeated dosing. Clinical context: Rapid clearance supports once-nightly dosing for sleep onset insomnia. |
| Protein binding | Approximately 70% bound to albumin. |
| Volume of Distribution | 1.3 L/kg (73.6 L for a 70 kg individual). This large Vd indicates extensive tissue distribution beyond plasma volume. |
| Bioavailability | Absolute oral bioavailability is approximately 1.8% due to extensive first-pass metabolism. However, clinical efficacy is achieved at low doses (8 mg). |
| Onset of Action | Oral: Median time to peak concentration is 0.75 hours (range 0.5-1.5 hours). Sleep onset is typically within 30-60 minutes post-dose. |
| Duration of Action | Approximately 6-8 hours. Clinical note: Duration is sufficient to promote sleep onset without significant residual sedation the next day due to short half-life. |
8 mg orally once daily within 30 minutes of bedtime.
| Dosage form | TABLET |
| Renal impairment | No dose adjustment required for mild to moderate renal impairment. Not studied in severe renal impairment (CrCl < 30 mL/min); use with caution. |
| Liver impairment | Child-Pugh Class A or B: no dose adjustment. Child-Pugh Class C: contraindicated due to increased exposure. |
| Pediatric use | Not approved for use in pediatric patients; safety and efficacy not established. |
| Geriatric use | No dose adjustment required. Use with caution due to potential for decreased metabolism and increased sensitivity. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for RAMELTEON (RAMELTEON).
| Breastfeeding | Ramelteon is excreted in rat milk; no human data available. M/P ratio unknown. Caution advised. Consider risk to infant vs benefit of therapy. |
| Teratogenic Risk | Pregnancy Category C. No adequate human studies. In animal studies, ramelteon caused reduced fetal body weight and delayed ossification at doses ≥ 32 mg/kg/day (approximately 22 times the human therapeutic dose of 8 mg based on AUC). Risk cannot be ruled out. Use only if potential benefit justifies potential risk to fetus. |
| Fetal Monitoring |
■ FDA Black Box Warning
None
| Serious Effects |
["Hypersensitivity to ramelteon or any component","Severe hepatic impairment (Child-Pugh Class C)"]
| Precautions | ["Angioedema","Severe allergic reactions","Abnormal thinking and behavioral changes","Complex sleep behaviors (e.g., sleep-driving)","Suicidal ideation","Exacerbation of depression","Hepatic impairment","Severe sleep apnea"] |
Loading safety data…
| No specific monitoring required. Standard prenatal care. Monitor for adverse effects such as dizziness, somnolence, and hormonal effects (e.g., decreased testosterone, increased prolactin). |
| Fertility Effects | In animal studies, ramelteon decreased fertility in male rats at high doses via hormonal disruption (decreased testosterone). No human data. Potential reversible effect on spermatogenesis. Advise patients of hormonal changes. |