Monitoring

No standard monitoring is required.

For patients presenting with unexplained amenorrhea, galactorrhea, decreased libido, or problems with fertility, assessment of prolactin levels and testosterone levels should be considered as appropriate.

Interference with Laboratory Tests

Ramelteon is not known to interfere with commonly used clinical laboratory tests. In addition, in vitro data indicate that ramelteon does not cause false-positive results for benzodiazepines, opiates, barbiturates, cocaine, cannabinoids, or amphetamines in two standard urine drug screening methods in vitro.

Adverse Reactions Resulting in Discontinuation of Treatment

The data described in this section reflect exposure to ramelteon in 5,373 subjects, including 722 exposed for six months or longer, and 448 subjects for one year.

Six percent of the 5,373 individual subjects exposed to ramelteon in clinical studies discontinued treatment owing to an adverse event, compared with 2% of the 2,279 subjects receiving placebo. The most frequent adverse events leading to discontinuation in subjects receiving ramelteon tablets were somnolence, dizziness, nausea, fatigue, headache, and insomnia; all of which occurred in 1% of the patients or less.

Ramelteon Most Commonly Observed Adverse Events

Table 1 displays the incidence of adverse events reported by the 2,861 patients with chronic insomnia who participated in placebo-controlled trials of ramelteon.

Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in clinical trials of other drugs, and may not reflect the rates observed in practice. The adverse reaction information from clinical trials does, however, provide a basis for identifying the adverse events that appear to be related to drug use and for approximating rates.

Fluvoxamine (strong CYP1A2 inhibitor)

AUC0-inf for ramelteon increased approximately 190-fold, and the Cmax increased approximately 70- fold upon coadministration of fluvoxamine and ramelteon, compared to ramelteon administered alone. Ramelteon should not be used in combination with fluvoxamine [see Contraindications (4), Clinical Pharmacology (12.5)]. Other less strong CYP1A2 inhibitors have not been adequately studied. Ramelteon should be administered with caution to patients taking less strong CYP1A2 inhibitors.

Rifampin (strong CYP enzyme inducer)

Administration of multiple doses of rifampin resulted in a mean decrease of approximately 80% in total exposure to ramelteon and metabolite M-II. Efficacy may be reduced when ramelteon is used in combination with strong CYP enzyme inducers such as rifampin [see Clinical Pharmacology (12.5)].

Ketoconazole (strong CYP3A4 inhibitor)

The AUC0-inf and Cmax of ramelteon increased by approximately 84% and 36% upon coadministration of ketoconazole with ramelteon. Ramelteon should be administered with caution in subjects taking strong CYP3A4 inhibitors such as ketoconazole [see Clinical Pharmacology (12.5)].

Fluconazole (strong CYP2C9 inhibitor)

The AUC0-inf and Cmax of ramelteon was increased by approximately 150% when ramelteon was coadministered with fluconazole. Ramelteon should be administered with caution in subjects taking strong CYP2C9 inhibitors such as fluconazole [see Clinical Pharmacology (12.5)].

Donepezil

The AUC0-inf and Cmax of ramelteon increased by approximately 100% and 87%, respectively upon coadministration of donepezil with ramelteon. Patients should be closely monitored when ramelteon is coadministered with donepezil [see Clinical Pharmacology (12.5)].

Doxepin

The AUC0-inf and Cmax of ramelteon increased by approximately 66% and 69%, respectively, upon coadministration of doxepin with ramelteon. Patients should be closely monitored when ramelteon is coadministered with doxepin [see Clinical Pharmacology (12.5)].

Risk Summary

Available data from postmarketing reports with ramelteon use in pregnant women have not identified a drug-associated risk of major birth defects, miscarriage, or adverse maternal or fetal outcomes. In animal studies, ramelteon produced evidence of developmental toxicity, including teratogenic effects, in rats at doses greater than 36 times the recommended human dose (RHD) of 8 mg/day based on body surface area (mg/m2) (see Data).

The estimated background risk of major birth defects and miscarriage for the indicated population is unknown. All pregnancies have a background risk of birth defect, loss, or other adverse outcomes. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2% to 4% and 15% to 20%, respectively.

Risk Summary

There are no data regarding the presence of ramelteon or its metabolites in human milk, the effects on the breastfed infant, or the effects on milk production. Ramelteon and/or its metabolites are present in rat milk. When a drug is present in animal milk, it is likely that the drug will be present in human milk. Because of the mechanism of action of ramelteon, there is a potential risk for somnolence in a breastfed infant (see Clinical Considerations). The developmental and health benefits of breastfeeding should be considered along with the mother's clinical need for ramelteon and any potential adverse effects on the breastfed infant from ramelteon tablets or from the underlying maternal condition.

Clinical Considerations

Infants exposed to ramelteon through breastmilk should be monitored for somnolence and feeding problems. A lactating woman may consider interrupting breastfeeding and pumping and discarding breast milk during treatment and for 25 hours (approximately 5 elimination half-lives) after ramelteon tablets administration in order to minimize drug exposure to a breastfed infant.

Absorption

Ramelteon is absorbed rapidly, with median peak concentrations occurring at approximately 0.75 hour (range, 0.5 to 1.5 hours) after fasted oral administration. Although the total absorption of ramelteon is at least 84%, the absolute oral bioavailability is only 1.8% due to extensive first-pass metabolism.

Distribution

In vitro protein binding of ramelteon is approximately 82% in human serum, independent of concentration. Binding to albumin accounts for most of that binding, since 70% of the drug is bound in human serum albumin. Ramelteon is not distributed selectively to red blood cells.

Ramelteon has a mean volume of distribution after intravenous administration of 73.6 L, suggesting substantial tissue distribution.

Metabolism

Metabolism of ramelteon consists primarily of oxidation to hydroxyl and carbonyl derivatives, with secondary metabolism producing glucuronide conjugates. CYP1A2 is the major isozyme involved in the hepatic metabolism of ramelteon; the CYP2C subfamily and CYP3A4 isozymes are also involved to a minor degree.

The rank order of the principal metabolites by prevalence in human serum is M-II, M-IV, M-I, and M-III. These metabolites are formed rapidly and exhibit a monophasic decline and rapid elimination. The overall mean systemic exposure of M-II is approximately 20- to 100-fold higher than parent drug.

Elimination

Following oral administration of radiolabeled ramelteon, 84% of total radioactivity was excreted in urine and approximately 4% in feces, resulting in a mean recovery of 88%. Less than 0.1% of the dose was excreted in urine and feces as the parent compound. Elimination was essentially complete by 96 hours postdose.

Repeated once daily dosing with ramelteon does not result in significant accumulation owing to the short elimination half-life of ramelteon (on average, approximately one to 2.6 hours).

The half-life of M-II is two to five hours and independent of dose. Serum concentrations of the parent drug and its metabolites in humans are at or below the lower limits of quantitation within 24 hours.

Effect of Food

When administered with a high-fat meal, the AUC0-inf for a single 16 mg dose of ramelteon was 31% higher and the Cmax was 22% lower than when given in a fasted state. Median Tmax was delayed by approximately 45 minutes when ramelteon was administered with food. Effects of food on the AUC values for M-II were similar. It is therefore recommended that ramelteon not be taken with or immediately after a high-fat meal [see Dosage and Administration (2.1)].

Age

In a group of 24 elderly subjects aged 63 to 79 years administered a single ramelteon 16 mg dose, the mean Cmax and AUC0-inf values were 11.6 ng/mL (SD, 13.8) and 18.7 ng∙hr/mL (SD, 19.4), respectively. The elimination half-life was 2.6 hours (SD, 1.1). Compared with younger adults, the total exposure (AUC0-inf) and Cmax of ramelteon were 97% and 86% higher, respectively, in elderly subjects. The AUC0-inf and Cmax of M-II were increased by 30% and 13%, respectively, in elderly subjects.

Gender

There are no clinically meaningful gender-related differences in the pharmacokinetics of ramelteon or its metabolites.

Hepatic Impairment

Exposure to ramelteon was increased almost four-fold in subjects with mild hepatic impairment after seven days of dosing with 16 mg/day; exposure was further increased (more than ten-fold) in subjects with moderate hepatic impairment. Exposure to M-II was only marginally increased in mildly and moderately impaired subjects relative to healthy matched controls. The pharmacokinetics of ramelteon have not been evaluated in subjects with severe hepatic impairment (Child-Pugh Class C). Ramelteon should be used with caution in patients with moderate hepatic impairment [see Warnings and Precautions (5.6)].

Renal Impairment

The pharmacokinetic characteristics of ramelteon were studied after administering a 16 mg dose to subjects with mild, moderate, or severe renal impairment based on predose creatinine clearance (53 to 95, 35 to 49, or 15 to 30 mL/min/1.73 m2, respectively), and in subjects who required chronic hemodialysis. Wide intersubject variability was seen in ramelteon exposure parameters. However, no effects on Cmax or AUC0-t of parent drug or M-II were seen in any of the treatment groups; the incidence of adverse events was similar across groups. These results are consistent with the negligible renal clearance of ramelteon, which is principally eliminated via hepatic metabolism. No adjustment of ramelteon dosage is required in patients with renal impairment, including patients with severe renal impairment (creatinine clearance of ≤30 mL/min/1.73 m2) and patients who require chronic hemodialysis.

Effects of Other Drugs on Ramelteon Metabolism

Effects of Ramelteon on Metabolism of Other Drugs

Effect of Alcohol on Ramelteon

With single-dose, daytime coadministration of ramelteon 32 mg and alcohol (0.6 g/kg), there were no clinically meaningful or statistically significant effects on peak or total exposure to ramelteon. However, an additive effect was seen on some measures of psychomotor performance (i.e., the Digit Symbol Substitution Test, the Psychomotor Vigilance Task Test, and a Visual Analog Scale of Sedation) at some postdose time points. No additive effect was seen on the Delayed Word Recognition Test. Because alcohol by itself impairs performance, and the intended effect of ramelteon is to promote sleep, patients should be cautioned not to consume alcohol when using ramelteon.

Carcinogenesis

Ramelteon was administered to mice and rats at oral doses of 0, 30, 100, 300, or 1,000 mg/kg/day (mice) and 0, 15, 60, 250, or 1,000 mg/kg/day (rats). Mice and rats were dosed for two years, except at the high dose (94 weeks for male and female mice and female rats). In mice, dose-related increases in the incidence of hepatic tumors (adenomas, carcinomas, hepatoblastomas) were observed in males and females. The no-effect dose for hepatic tumors in mice (30 mg/kg/day) is approximately 20 times the recommended human dose (RHD) of 8 mg/day based on body surface area (mg/m2).

In rats, the incidence of hepatic adenoma and benign Leydig cell tumors of the testis was increased in males at doses ≥250 mg/kg/day. In females, the incidence of hepatic adenoma was increased at doses ≥60 mg/kg/day. The incidence of hepatic carcinoma was increased in males and female rats at 1,000 mg/kg/day. The no-effect dose for tumors in rats (15 mg/kg/day) is approximately 20 times the RHD based on mg/m2.

Mutagenesis

Ramelteon was not genotoxic in the in vitro bacterial reverse mutation (Ames) assay, the in vitro mouse lymphoma TK+/- assay, and in in vivo oral micronucleus assays in mouse and rat. Ramelteon was clastogenic in the in vitro chromosomal aberration assay in Chinese hamster lung cells.

The M-II metabolite was not tested for genotoxicity. However, it was present in the test medium of the parent drug at concentrations higher than those of the parent.

Impairment of Fertility

When ramelteon (doses of 6 to 600 mg/kg/day) was administered orally to male and female rats prior to and during mating and early gestation, alterations in estrus cyclicity and decreased numbers of corpora lutea, implantations, and live embryos were observed at doses greater than 20 mg/kg/day. The no-effect dose is approximately 24 times the RHD of 8 mg/day based on mg/m2. Oral administration of ramelteon (up to 600 mg/kg/day) to male rats had no effects on sperm quality or reproductive performance.

Chronic Insomnia

Three randomized, double-blind trials in subjects with chronic insomnia employing polysomnography (PSG) were provided as objective support of ramelteon's effectiveness in sleep initiation.

One study enrolled younger adults (aged 18 to 64 years, inclusive) with chronic insomnia and employed a parallel design in which the subjects received a single, nightly dose of ramelteon tablets (8 or 16 mg) or matching placebo for 35 days. PSG was performed on the first two nights in each of Weeks 1, 3, and 5 of treatment. Ramelteon reduced the average latency to persistent sleep at each of the time points when compared to placebo. The 16 mg dose conferred no additional benefit for sleep initiation.

The second study employing PSG was a three-period crossover trial performed in subjects aged 65 years and older with a history of chronic insomnia. Subjects received ramelteon tablets (4 or 8 mg) or placebo and underwent PSG assessment in a sleep laboratory for two consecutive nights in each of the three study periods. Both doses of ramelteon reduced latency to persistent sleep when compared to placebo.

The third study evaluated long-term efficacy and safety in adults with chronic insomnia. Subjects received a single, nightly dose of ramelteon tablets 8 mg or matching placebo for six months. PSG was performed on the first two nights of Week 1 and Months 1, 3, 5, and 6. Ramelteon reduced sleep latency at each time point when compared to placebo. In this study, when the PSG results from nights 1 and 2 of Month 7 were compared to the results from nights 22 and 23 of Month 6, there was a statistically significant increase in LPS of 33% (9.5 minutes) in the ramelteon group. There was no increase in LPS in the placebo group when the same time periods were compared.

A randomized, double-blind, parallel group study was conducted in outpatients aged 65 years and older with chronic insomnia and employed subjective measures of efficacy (sleep diaries). Subjects received ramelteon tablets (4 or 8 mg) or placebo for 35 nights. Ramelteon reduced patient-reported sleep latency compared to placebo. A similarly designed study performed in younger adults (aged 18 to 64 years) using 8 and 16 mg of ramelteon did not replicate this finding of reduced patient- reported sleep latency compared to placebo.

While the 16 mg dose was evaluated as a potential treatment for adults, it was shown to confer no additional benefit for sleep initiation and was associated with higher incidences of fatigue, headache and next-day somnolence.

Transient Insomnia

In a randomized, double-blind, parallel-group trial using a first-night-effect model, healthy adults received placebo or ramelteon before spending one night in a sleep laboratory and being evaluated with PSG. Ramelteon demonstrated a decrease in mean latency to persistent sleep as compared to placebo.

Results from Human Laboratory Abuse Liability Studies

A human laboratory abuse potential study was performed in 14 subjects with a history of sedative/hypnotic or anxiolytic drug abuse. Subjects received single oral doses of ramelteon tablets (16, 80, or 160 mg), triazolam (0.25, 0.50, or 0.75 mg) or placebo. All subjects received each of the seven treatments separated by a wash-out period and underwent multiple standard tests of abuse potential. No differences in subjective responses indicative of abuse potential were found between ramelteon and placebo at doses up to 20 times the recommended therapeutic dose. The positive control drug, triazolam, consistently showed a dose-response effect on these subjective measures, as demonstrated by the differences from placebo in peak effect and overall 24-hour effect.

Residual Pharmacological Effect in Insomnia Trials

In order to evaluate potential next-day residual effects, the following scales were used: a Memory Recall Test, a Word List Memory Test, a Visual Analog Mood and Feeling Scale, the Digit-Symbol Substitution Test, and a post sleep questionnaire to assess alertness and ability to concentrate. There was no evidence of next-day residual effect seen after two nights of ramelteon use during the crossover studies.

In a 35 night, double-blind, placebo-controlled, parallel-group study in adults with chronic insomnia, measures of residual effects were performed at three time points. Overall, the magnitudes of any observed differences were small. At Week 1, patients who received 8 mg of ramelteon had a mean VAS score (46 mm on a 100 mm scale) indicating more fatigue in comparison to patients who received placebo (42 mm). At Week 3, patients who received 8 mg of ramelteon tablets had a lower mean score for immediate recall (7.5 out of 16 words) compared to patients who received placebo (8.2 words); and the patients treated with ramelteon had a mean VAS score indicating more sluggishness (27 mm on a 100 mm VAS) in comparison to the placebo-treated patients (22 mm). Patients who received ramelteon did not have next-morning residual effects that were different from placebo at Week 5.