Ramelteon

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Ramelteon is a melatonin receptor agonist used in the treatment of insomnia. It is marketed under the brand name Rozerem. Ramelteon is notable for its selective action on the MT1 and MT2 receptors in the suprachiasmatic nucleus of the brain, which are involved in the regulation of the sleep-wake cycle.

Mechanism of Action

Ramelteon works by mimicking the action of melatonin, a naturally occurring hormone that regulates sleep. By binding to the MT1 and MT2 receptors, Ramelteon helps to promote the onset of sleep and regulate the circadian rhythm. Unlike other sleep aids, Ramelteon does not act on the GABA receptors, which means it has a lower risk of dependence and withdrawal symptoms.

Indications

Ramelteon is primarily indicated for the treatment of insomnia characterized by difficulty with sleep onset. It is particularly useful for patients who have trouble falling asleep but do not necessarily have issues with staying asleep.

Dosage and Administration

Ramelteon is typically prescribed in a dose of 8 mg, taken about 30 minutes before bedtime. It should not be taken with or immediately after a high-fat meal, as this can delay its absorption and onset of action.

Side Effects

Common side effects of Ramelteon include:

• Dizziness
• Fatigue
• Somnolence
• Nausea

Less common but more serious side effects may include:

• Allergic reactions
• Hormonal imbalances

Contraindications

Ramelteon is contraindicated in patients with a history of hypersensitivity to the drug or any of its components. It should also be used with caution in patients with severe hepatic impairment.

Drug Interactions

Ramelteon may interact with other medications, including:

• Fluvoxamine, which can increase Ramelteon levels
• Ketoconazole and fluconazole, which can also increase Ramelteon levels
• Rifampin, which can decrease Ramelteon levels

Pharmacokinetics

Ramelteon is rapidly absorbed, with peak plasma concentrations occurring about 45 minutes after oral administration. It is extensively metabolized in the liver, primarily by the CYP1A2 enzyme, and has a half-life of approximately 1-2.6 hours.

Regulatory Status

Ramelteon was approved by the Food and Drug Administration (FDA) in 2005 for the treatment of insomnia characterized by difficulty with sleep onset.

See Also

• Melatonin
• Insomnia
• Circadian rhythm
• Sleep disorder