Ramelteon is developed and produced by Takeda Pharmaceutical Company. It is a selective agonist of MT1 and MT2 melatonin receptors. Ramelteon regulates the sleep-wake cycle by simulating the mechanism of action of endogenous melatonin.
Indications of Ramelteon
Main Therapeutic Uses
Ramelteon is specifically used for the treatment of insomnia characterized by difficulty in falling asleep.
Characteristics of Applicable Populations
Adult patients (aged 18-64 years) with chronic insomnia.
Elderly patients (aged 65 years and above) with chronic insomnia.
Transient insomnia in healthy adults (based on the "first-night effect" model).
Usage Restrictions and Contraindications
Patients who are allergic to Ramelteon or any component in the preparation.
Patients with severe hepatic impairment (Child-Pugh Class C).
Concomitant use with fluvoxamine (as it significantly increases drug exposure).
Patients with severe sleep apnea or severe chronic obstructive pulmonary disease (COPD).
Specifications and Properties of Ramelteon
Basic Chemical Properties
Chemical Structure: (S)-N-[2-(1,6,7,8-Tetrahydro-2H-indeno[5,4-b]furan-8-yl)ethyl]propanamide.
Molecular Formula: C₁₆H₂₁NO₂.
Molecular Weight: 259.34.
Solubility: Easily soluble in organic solvents such as methanol and ethanol, slightly soluble in water (extremely low solubility in pH 3-11 buffer solutions).
Preparation Specifications
Dosage Form: Film-coated tablets.
Strength: 8 mg per tablet (round, pale orange-yellow tablets, engraved with "TAK" and "RAM-8" markings).
Excipient Components: Lactose monohydrate, starch, hydroxypropyl cellulose, magnesium stearate, etc. The coating contains colorants such as titanium dioxide and yellow iron oxide.
Pharmacokinetic Characteristics
Absorption: After oral administration on an empty stomach, the peak concentration is reached at 0.75 hours, with an absolute bioavailability of only 1.8% (significant first-pass effect).
Metabolism: Mainly metabolized through CYP1A2 oxidation. The systemic exposure of the active metabolite M-II is 20-100 times that of the parent drug.
Elimination: The half-life is 1-2.6 hours, and 88% of the drug is excreted through urine (parent drug accounts for <0.1%).
Storage Methods of Ramelteon
Storage Conditions for Original Packaging
Temperature: Store at 25°C (77°F).
Brief exposure to 15-30°C (59-86°F) is allowed.
Keep the container tightly closed.
Protect from moisture.
Avoid light exposure.
Storage Recommendations for Special Populations
Ensure that the storage conditions meet the standard requirements.
Patients with moderate hepatic impairment should use it with caution.
No dosage adjustment is required for patients with renal impairment.
The drug should be stored out of the reach of children.
