Tasimelteon
Capsule · Oral
Uses
Tasimelteon is a melatonin receptor agonist. Tasimelteon capsules are indicated for the treatment of: Non-24-Hour Sleep-Wake Disorder (Non-24) in adults ( 1 ) 1.1 Non-24-Hour Sleep-Wake Disorder (Non-24) Tasimelteon capsules are indicated for the treatment of Non-24 in adults.
Dosage and administration
Indicated Population Dosage Form Body Weight Recommended Dosage Non-24 ( 2.2 ) Adults Capsules Not applicable 20 mg one hour prior to bedtime Administer at the same time every night (2.2) Take without food ( 2.4 ) 2.2 Recommended Dosage for Tasimelteon Capsules for Non-24 Adults The recommended dosage of tasimelteon capsules in adults is 20 mg one hour before bedtime, at the same time every night. Because of individual differences in circadian rhythms, drug effect may not occur for weeks or months. 2.4 Important Administration Information Administer tasimelteon capsules without food [see Clinical Pharmacology (12.3)] . If a patient is unable to take tasimelteon capsules at approximately the same time on a given night, they should skip that dose and take the next dose as scheduled.
Dosage forms and strengths
Capsules: Each size 1 hard gelatin capsule with light blue opaque cap and body imprinted with A44 on cap in black ink contains white to off-white color granular powder. Capsules: 20 mg ( 3 )
Contraindications
None. None ( 4 )
Warnings and precautions
May cause somnolence: After taking tasimelteon capsules, patients should limit their activity to preparing for going to bed, because tasimelteon can impair the performance of activities requiring complete mental alertness ( 5.1 ) 5.1 Somnolence After taking tasimelteon capsules, patients should limit their activity to preparing for going to bed. Tasimelteon can potentially impair the performance of activities requiring complete mental alertness.
Side effects
The most common adverse reactions (incidence >5% and at least twice as high on tasimelteon than on placebo) were headache, increased alanine aminotransferase, nightmares or unusual dreams, and upper respiratory or urinary tract infection ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Teva at 1-888-838-2872 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch . 6.1 Clinical Trials Experience 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 the clinical trials of another drug and may not reflect the rates observed in clinical practice. More than 2080 subjects have been treated with at least one dose of tasimelteon, of which more than 380 have been treated for > 26 weeks and more than 170 have been treated for > 1 year. Non-24-Hour Sleep-Wake Disorder (Non-24) A 26-week, parallel-arm placebo-controlled study (Study 1) evaluated tasimelteon (n=42) compared to placebo (n=42) in patients with Non-24. A randomized-withdrawal, placebo-controlled study of 8 weeks duration (Study 2) also evaluated tasimelteon (n=10), compared to placebo (n=10), in patients with Non-24. In placebo-controlled studies, 6% of patients exposed to tasimelteon discontinued treatment due to an adverse event, compared with 4% of patients who received placebo. Table 2 shows the incidence of adverse reactions from Study 1. Table 2: Adverse Reactions in Study 1 Tasimelteon N=42 Placebo N=42 Headache 17% 7% Alanine aminotransferase increased 10% 5% Nightmare/abnormal dreams 10% 0% Upper respiratory tract infection 7% 0% Urinary tract infection 7% 2% *Adverse reactions with an incidence >5% and at least twice as high on tasimelteon than on placebo are displayed.
Drug interactions
Strong CYP1A2 inhibitors (e.g., fluvoxamine): Avoid use of tasimelteon in combination with strong CYP1A2 inhibitors because of increased exposure ( 7.1 , 12.3 ) Strong CYP3A4 inducers (e.g., rifampin): Avoid use of tasimelteon in combination with rifampin or other CYP3A4 inducers, because of decreased exposure ( 7.2 , 12.3 ) 7.1 Strong CYP1A2 Inhibitors (e.g., fluvoxamine) Avoid use of tasimelteon in combination with fluvoxamine or other strong CYP1A2 inhibitors because of a potentially large increase in tasimelteon exposure and greater risk of adverse reactions [see Clinical Pharmacology ( 12.3 )] . 7.2 Strong CYP3A4 Inducers (e.g., rifampin) Avoid use of tasimelteon in combination with rifampin or other CYP3A4 inducers because of a potentially large decrease in tasimelteon exposure with reduced efficacy [see Clinical Pharmacology ( 12.3 )] . 7.3 Beta-Adrenergic Receptor Antagonists (e.g., acebutolol, metoprolol) Beta-adrenergic receptor antagonists have been shown to reduce the production of melatonin via specific inhibition of beta-1 adrenergic receptors. Nighttime administration of beta- adrenergic receptor antagonists may reduce the efficacy of tasimelteon.
Use in specific populations
Hepatic impairment : Tasimelteon has not been studied in patients with severe hepatic impairment and is not recommended in these patients ( 8.6 ) 8.1 Pregnancy Risk Summary Available postmarketing case reports with tasimelteon use in pregnant women are not sufficient to evaluate drug-associated risk of major birth defects, miscarriage or adverse maternal or fetal outcomes. In pregnant rats, no embryofetal developmental toxicity was observed at exposures of 50 mg/kg/day, or up to 24 times higher than the human exposure at the maximum recommended human dose (MRHD) (see Data). The estimated background risk of major birth defects and miscarriage for the indicated populations are unknown. 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. Data Animal Data In pregnant rats administered tasimelteon at oral doses of 5 mg/kg/day, 50 mg/kg/day, or 500 mg/kg/day during the period of organogenesis, there were no effects on embryofetal development. The highest dose tested is approximately 240 times the MRHD of 20 mg/day, based on mg/m 2 body surface area. In pregnant rabbits administered tasimelteon at oral doses of 5 mg/kg/day, 30 mg/kg/day, or 200 mg/kg/day during the period of organogenesis, embryolethality and embryofetal toxicity (reduced fetal body weight and delayed ossification) were observed at the highest dose tested. The highest dose is approximately 200 times the MRHD. Oral administration of tasimelteon at 50 mg/kg/day, 150 mg/kg/day, or 450 mg/kg/day to rats throughout organogenesis resulted in persistent reductions in body weight, delayed sexual maturation, and physical development, and neurobehavioral impairment in offspring at the highest dose tested which is approximately 220 times the MRHD based on mg/m 2 body surface area. Reduced body weight in offspring was also observed at the mid-dose. The no effect dose (NOEL), (50 mg/kg/day) is approximately 25 times the MRHD based on mg/m 2 body surface area. 8.2 Lactation Risk Summary There are no data on the presence of tasimelteon or its metabolites in human or animal milk, the effects on the breastfed infant, or the effects on milk production. The developmental and health benefits of breastfeeding should be considered along with the mother’s clinical need for tasimelteon and any potential adverse effects on the breastfed infant from tasimelteon or from the underlying maternal condition. 8.4 Pediatric Use Safety and effectiveness of tasimelteon for the treatment of Non-24 in pediatric patients have not been established. Juvenile Animal Toxicity Data Juvenile rats received oral doses of tasimelteon at 50, 150, or 450 mg/kg from weaning (day 21) through adulthood (day 90). These doses are approximately 12 to 108 times the maximum recommended human dose (MRHD) of 20 mg based on a mg/m 2 body surface area. Toxicity was observed mainly at the highest dose and included mortality (females only), tremors, unsteady gait, decrease in growth and development compared to controls. The former reflected as decreases in bone growth, bone mineral content, bone ossification, and a delay in attainment of sexual maturation. Tasimelteon had no effect on fertility, reproduction, or learning and memory. The No Observed Adverse Effect Level (NOAEL) is 150 mg/kg/day, which is approximately 178 times the MRHD based on AUC. 8.5 Geriatric Use The risk of adverse reactions may be greater in elderly (>65 years) patients than younger patients because exposure to tasimelteon is increased by approximately 2-fold compared with younger patients. 8.6 Hepatic Impairment Dose adjustment is not necessary in patients with mild or moderate hepatic impairment. Tasimelteon has not been studied in patients with severe hepatic impairment (Child-Pugh Class C). Therefore, tasimelteon is not recommended for use in patients with severe hepatic impairment [see Clinical Pharmacology ( 12.3 )] . 8.7 Smokers Smoking causes induction of CYP1A2 levels. The exposure of tasimelteon in smokers was lower than in non-smokers and therefore the efficacy of tasimelteon may be reduced in smokers [see Clinical pharmacology ( 12.3 )] .
Pregnancy
8.1 Pregnancy Risk Summary Available postmarketing case reports with tasimelteon use in pregnant women are not sufficient to evaluate drug-associated risk of major birth defects, miscarriage or adverse maternal or fetal outcomes. In pregnant rats, no embryofetal developmental toxicity was observed at exposures of 50 mg/kg/day, or up to 24 times higher than the human exposure at the maximum recommended human dose (MRHD) (see Data). The estimated background risk of major birth defects and miscarriage for the indicated populations are unknown. 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. Data Animal Data In pregnant rats administered tasimelteon at oral doses of 5 mg/kg/day, 50 mg/kg/day, or 500 mg/kg/day during the period of organogenesis, there were no effects on embryofetal development. The highest dose tested is approximately 240 times the MRHD of 20 mg/day, based on mg/m 2 body surface area. In pregnant rabbits administered tasimelteon at oral doses of 5 mg/kg/day, 30 mg/kg/day, or 200 mg/kg/day during the period of organogenesis, embryolethality and embryofetal toxicity (reduced fetal body weight and delayed ossification) were observed at the highest dose tested. The highest dose is approximately 200 times the MRHD. Oral administration of tasimelteon at 50 mg/kg/day, 150 mg/kg/day, or 450 mg/kg/day to rats throughout organogenesis resulted in persistent reductions in body weight, delayed sexual maturation, and physical development, and neurobehavioral impairment in offspring at the highest dose tested which is approximately 220 times the MRHD based on mg/m 2 body surface area. Reduced body weight in offspring was also observed at the mid-dose. The no effect dose (NOEL), (50 mg/kg/day) is approximately 25 times the MRHD based on mg/m 2 body surface area.
Pediatric use
8.4 Pediatric Use Safety and effectiveness of tasimelteon for the treatment of Non-24 in pediatric patients have not been established. Juvenile Animal Toxicity Data Juvenile rats received oral doses of tasimelteon at 50, 150, or 450 mg/kg from weaning (day 21) through adulthood (day 90). These doses are approximately 12 to 108 times the maximum recommended human dose (MRHD) of 20 mg based on a mg/m 2 body surface area. Toxicity was observed mainly at the highest dose and included mortality (females only), tremors, unsteady gait, decrease in growth and development compared to controls. The former reflected as decreases in bone growth, bone mineral content, bone ossification, and a delay in attainment of sexual maturation. Tasimelteon had no effect on fertility, reproduction, or learning and memory. The No Observed Adverse Effect Level (NOAEL) is 150 mg/kg/day, which is approximately 178 times the MRHD based on AUC.
Geriatric use
8.5 Geriatric Use The risk of adverse reactions may be greater in elderly (>65 years) patients than younger patients because exposure to tasimelteon is increased by approximately 2-fold compared with younger patients.
Overdosage
There is limited premarketing clinical experience with the effects of an overdosage of tasimelteon. As with the management of any overdose, general symptomatic and supportive measures should be used, along with immediate gastric lavage where appropriate. Intravenous fluids should be administered as needed. Respiration, pulse, blood pressure, and other appropriate vital signs should be monitored, and general supportive measures employed. While hemodialysis was effective at clearing tasimelteon and the majority of its major metabolites in patients with renal impairment, it is not known if hemodialysis will effectively reduce exposure in the case of overdose. As with the management of any overdose, the possibility of multiple drug ingestion should be considered. Contact a poison control center for current information on the management of overdose.
Description
Tasimelteon is a melatonin receptor agonist, chemically designated as (1 R , 2 R )-N-[2- (2,3-dihydrobenzofuran-4-yl)cyclopropylmethyl]propanamide, containing two chiral centers. The molecular formula is C 15 H 19 NO 2 , and the molecular weight is 245.32. The structural formula is: Tasimelteon is a white to off-white crystalline powder. It is very slightly soluble in cyclohexane, slightly soluble in water and 0.1 N hydrochloric acid, and freely soluble or very soluble in methanol, 95% ethanol, acetonitrile, isopropanol, polyethylene glycol 300, propylene glycol and ethyl acetate. Tasimelteon is available in 20 mg strength capsules for oral administration. Inactive ingredients are colloidal silicon dioxide, croscarmellose sodium, lactose anhydrous, magnesium stearate, and microcrystalline cellulose. Each capsule shell consists of FD&C Blue No. 1, FD&C Red No. 40, gelatin, sodium lauryl sulfate, and titanium dioxide. The imprinting ink contains black iron oxide, potassium hydroxide, propylene glycol, and shellac. 1
Mechanism of action
12.1 Mechanism of Action The mechanism by which tasimelteon exerts its therapeutic effect in patients with Non-24 is unclear. However, tasimelteon is an agonist at melatonin MT 1 and MT 2 receptors which are thought to be involved in the control of circadian rhythms.
How supplied
Tasimelteon capsules are available as follows: 20 mg – Each size 1 hard gelatin capsule with light blue opaque cap and body imprinted with A44 on cap in black ink contains white to off-white color granular powder. Capsules are supplied in bottles of 30 (NDC 0480-4490-56). Storage and Handling Store at 25°C (77°F); excursions permitted to 15° to 30°C (59° to 86°F) [see USP Controlled Room Temperature]. Protect from exposure to light and moisture.
Patient information
Advise patients to limit their activities to preparing for going to bed after taking tasimelteon capsules because tasimelteon can potentially impair the performance of activities requiring complete mental alertness [see Warnings and Precautions ( 5.1 )] . Administration Information for tasimelteon capsules [see Dosage and Administration ( 2.2 , 2.4 )] . Advise patients to take tasimelteon without food. Advise patients to take tasimelteon before bedtime at the same time every night. Advise patients to skip the dose that night if they cannot take tasimelteon at approximately the same time on a given night. Advise patients to swallow tasimelteon capsules whole. Advise patients that because of individual differences in circadian rhythms, daily use for several weeks or months may be necessary before benefit from tasimelteon capsules is observed [see Dosage and Administration ( 2.2 )] . Manufactured in India By: Watson Pharma Private Limited Verna, Salcette Goa 403 722 INDIA Manufactured For: Teva Pharmaceuticals Parsippany, NJ 07054 Rev. A 8/2026
Label text from the FDA structured product label by Teva Pharmaceuticals, Inc. (revised Aug 18, 2026). Long sections are shortened; the complete label is on DailyMed.
Active ingredients
- Tasimelteon in 3 products
Tasimelteon NDC products (3)
| NDC | Strength & form | Labeler | Type |
|---|---|---|---|
| 69238-2548 | Tasimelteon 20 mg/1 Capsule | Amneal Pharmaceuticals NY LLC | ANDA |
| 60505-4665 | Tasimelteon 20 mg/1 Capsule | Apotex Corp. | ANDA |
| 0480-4490 | Tasimelteon 20 mg/1 Capsule, Gelatin Coated | Teva Pharmaceuticals, Inc. | ANDA |
Frequently asked questions
What is Tasimelteon used for?
Tasimelteon is a melatonin receptor agonist. Tasimelteon capsules are indicated for the treatment of: Non-24-Hour Sleep-Wake Disorder (Non-24) in adults ( 1 ) 1.1 Non-24-Hour Sleep-Wake Disorder (Non-24) Tasimelteon capsules are indicated for the treatment of Non-24 in adults.
What are the side effects of Tasimelteon?
The most common adverse reactions (incidence >5% and at least twice as high on tasimelteon than on placebo) were headache, increased alanine aminotransferase, nightmares or unusual dreams, and upper respiratory or urinary tract infection ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Teva at 1-888-838-2872 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch . 6.1 Clinical Trials Experience… See the full label for the complete list.
Who makes Tasimelteon?
Tasimelteon is listed by 3 labelers in the FDA NDC directory, including Amneal Pharmaceuticals NY LLC, Apotex Corp., Teva Pharmaceuticals, Inc..