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Tasimelteon

Tasimelteon is a melatonin receptor agonist used to treat Non-24-Hour Sleep-Wake Disorder in adults and nighttime sleep disturbances in Smith-Magenis Syndrome.

Brand names HetliozHetlioz LQ
Drug class Melatonin Receptor Agonist
Rx Forms 2
Dr. Brian Staiger, PharmD, BCPS
Reviewed by Last reviewed Jul 10, 2026 Content updated Oct 2, 2026
🧬 Where this information comes from Click to expand

The clinical label records used on this page are FDA-filed Structured Product Labeling (SPL) retrieved through openFDA. We identified 4 clinical label sets within the page’s selected clinical scope after exact ingredient or ingredient-combination matching and applicable route/form matching. Forms, routes, brands, labelers, strengths, and NDC product-record counts are built separately from matching FDA National Drug Code Directory records. The linked DailyMed document is a representative official source for verification, not the page’s only clinical source. View the linked label on DailyMed →

✓No current FDA shortage listed · checked Oct 5, 2026
Tasimelteon at a glance The quick version — the full detail is in the Patient Information Guide below.
Dr. Brian Staiger, PharmD, BCPS
The Pharmacist’s Take By · Clinical pharmacist · Written

Tasimelteon is a specialist medicine that switches on the brain's melatonin receptors to reset the body's internal clock, used for Non-24-Hour Sleep-Wake Disorder (sleep times that drift around the clock) in adults and for nighttime sleep disturbances in Smith-Magenis Syndrome, on the market since about 2014 and available generically. It is generally well tolerated, and headache, unusual dreams and sleepiness after the dose are what people notice most. That sleepiness is the thing to respect, so take it about an hour before bed and do nothing afterward but get ready to sleep. The full benefit can take weeks or months, so stick with the same time each night.

Clinical pearls

  • Take it on an empty stomach, because food, especially a high-fat dinner, sharply cuts how much of it you absorb.
  • Avoid fluvoxamine and rifampin with it, and a beta-blocker such as metoprolol taken at night may blunt its effect.
  • Smoking lowers tasimelteon levels and can weaken its effect, so tell your prescriber if you smoke or quit.
  • Hetlioz capsules and Hetlioz LQ oral suspension are not interchangeable, so never substitute one for the other.
How we write & review this content — our editorial policy →
How you get itPrescription only
Comes asCapsule, Oral suspension
Earliest FDA record2014
Companies listing it with the FDA4
FDA label last updatedAug 4, 2026
FDA’s strongest warning (boxed)None on the label

Patient information guide A plain-language walkthrough of Tasimelteon, written from its FDA label.

What Tasimelteon is used for

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Tasimelteon is a melatonin receptor agonist approved to treat sleep-timing disorders across several products and age groups.

  • Tasimelteon capsules (including Hetlioz capsules) are approved to treat Non-24-Hour Sleep-Wake Disorder (Non-24) in adults — a condition where the body's internal clock keeps drifting, causing sleep and wake times to shift around the clock over time.
  • Hetlioz capsules are approved to treat nighttime sleep disturbances in Smith-Magenis Syndrome (SMS) in patients 16 years of age and older.
  • Hetlioz LQ oral suspension is approved to treat nighttime sleep disturbances in SMS in pediatric patients ages 3 to 15 years.

How Tasimelteon works

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Tasimelteon activates two melatonin receptors in the brain — MT1 and MT2 — that are thought to play a key role in controlling the body's internal 24-hour clock (circadian rhythm). By stimulating these receptors, tasimelteon may help shift the body's sleep-wake cycle back into a normal pattern. It has a stronger attraction to the MT2 receptor than the MT1 receptor. The precise way this translates into benefit for Non-24 or SMS is not fully understood.

Tasimelteon dosage

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Tasimelteon is taken by mouth once a night, about one hour before bedtime — always at the same time each night. It must be taken on an empty stomach; eating (especially a high-fat meal) can substantially reduce how much drug your body absorbs and delay its effect. If you miss your usual time on a given night, skip that dose entirely and take the next dose on schedule — do not double up.

  • Hetlioz capsules and Hetlioz LQ oral suspension are not interchangeable — the two forms are dosed differently and should not be swapped.
  • Because everyone's circadian rhythm is different, it may take weeks or months of consistent nightly use before the full effect is seen.

Dosing details from the FDA-approved label

From the Tasimelteon prescribing information (“Dosage and Administration”). Doses are set by your prescriber for your product, condition, kidney function and age — never change a dose on your own.

  • Non-24-Hour Sleep-Wake Disorder (Non-24) in adults (capsules)
    • 20 mg one hour before bedtime, at the same time every night
    • Take without food; drug effect may not occur for weeks or months; if unable to take at approximately the same time, skip that dose and take the next dose as scheduled
  • Nighttime sleep disturbances in Smith-Magenis Syndrome (SMS), patients 16 years of age and older (capsules)
    • 20 mg one hour before bedtime, at the same time every night
    • Take without food
  • Nighttime sleep disturbances in SMS, pediatric patients 3 to 15 years of age, body weight ≤28 kg (oral suspension)
    • 0.7 mg/kg one hour before bedtime, at the same time every night
    • Take without food; capsules and oral suspension are not substitutable
  • Nighttime sleep disturbances in SMS, pediatric patients 3 to 15 years of age, body weight >28 kg (oral suspension)
    • 20 mg one hour before bedtime, at the same time every night
    • Take without food; capsules and oral suspension are not substitutable
Read the label’s full dosing text

2 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 Nighttime sleep disturbances in SMS ( 2.3 ) Patients 16 years of age and older Capsules Not applicable 20 mg one hour prior to bedtime Pediatric Patients 3 to 15 years of age Oral Suspension ≤ 28 kg 0.7 mg/kg one hour before bedtime ≥ 28 kg 20 mg one hour prior to bedtime HETLIOZ capsules and HETLIOZ LQ oral suspension are not substitutable ( 2.1 ) Administer at the same time every night ( 2.2 , 2.3 ) Take without food ( 2.4 ) 2.1 Non-Interchangeability between HETLIOZ Capsules and HETLIOZ LQ Oral Suspension HETLIOZ capsules and HETLIOZ LQ oral suspension are not substitutable [see Clinical Pharmacology ( 12.3 )]. 2.2 Recommended Dosage for HETLIOZ Capsules for Non-24 Adults The recommended dosage of HETLIOZ 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. 2.3 Recommended Dosage for HETLIOZ Capsules and HETLIOZ LQ Oral Suspension for Nighttime Sleep Disturbances in SMS Patients 16 years of Age and Older The recommended dosage of HETLIOZ capsules in patients 16 years and older is 20 mg one hour before bedtime, at the same time every night. Pediatric Patients 3 Years to 15 Years of Age The recommended dosage of HETLIOZ LQ oral suspension in pediatric patients 3 years to 15 years of age is based on body weight ( Table 1 ). Administer HETLIOZ one hour before bedtime, at the same time every night. Table 1: Recommended Dosage of HETLIOZ LQ Oral Suspension for the Treatment of Nighttime Sleep Disturbances in SMS in Pediatric Patients 3 Years to 15 Years of Age Body Weight Daily Dose (oral suspension) ≤28 kg 0.7 mg/kg one hour before bedtime >28 kg 20 mg one hour before bedtime 2.4 Important Administration Information Administer HETLIOZ capsules and HETLIOZ LQ oral suspension without food [see Clinical Pharmacology ( 12.3 )] . If a patient is unable to take HETLIOZ at approximately the same time on a given night, they should skip that dose and take the next dose as scheduled. HETLIOZ LQ Oral Suspension See " Instructions for Use " for complete administration instructions. Shake HETLIOZ LQ oral suspension well for at least 30 seconds before every administration.

Excerpted — the section continues on the label. Read the full Dosage and Administration section on DailyMed →

Tasimelteon side effects

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The most commonly reported side effects include:

Common side effects

  • Headache
  • Elevated liver enzyme (alanine aminotransferase) levels
  • Nightmares or unusual dreams
  • Upper respiratory tract infection
  • Urinary tract infection
  • Drowsiness or sleepiness after taking the dose
  • Elevated alanine aminotransferase (a liver enzyme) levels in blood tests

When to get medical help

  • Call your doctor if you notice signs of liver problems, such as unusual tiredness, yellowing of the skin or eyes, or dark urine — elevated liver enzymes have been reported
  • Contact your doctor if drowsiness feels severe or is affecting your safety during waking hours

Drowsiness is expected — that's part of how the medicine works — but it means you should go straight to bed after taking it and not drive or use machinery. If you notice signs of liver problems (unusual fatigue, yellowing of skin or eyes) or if drowsiness feels overwhelming, contact your doctor.

Tasimelteon warnings and precautions

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  • Drowsiness: Tasimelteon can impair your ability to perform tasks that require full mental alertness. After taking your dose, limit your activity to preparing for bed.
  • Severe liver disease: Hetlioz has not been studied in patients with severe hepatic impairment and is not recommended for them. Mild or moderate liver impairment does not require a dose change, but let your doctor know.
  • Older adults: People over 65 have about twice as much tasimelteon in their blood compared to younger adults, which may increase the chance of side effects.
  • Smokers: Smoking lowers the amount of tasimelteon in the body, which may reduce how well it works.

Tasimelteon interactions

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Several drugs and substances can affect how tasimelteon works in your body:

  • Strong CYP1A2 inhibitors (e.g., fluvoxamine): These drugs block an enzyme that breaks down tasimelteon, causing drug levels to rise significantly — avoid this combination.
  • Strong CYP3A4 inducers (e.g., rifampin): These speed up tasimelteon's breakdown, lowering its levels in the blood and reducing effectiveness — avoid this combination.
  • Beta-blockers (e.g., acebutolol, metoprolol) taken at night: These medications can reduce natural melatonin production, which may make tasimelteon less effective.
  • Smoking: Cigarette smoke induces the enzyme CYP1A2, which clears tasimelteon faster — smokers may have lower drug levels and reduced benefit.

Interactions listed in the FDA-approved label

From the Tasimelteon prescribing information (“Drug Interactions”): what the manufacturer studied or reported to the FDA.

  • Strong CYP1A2 inhibitors (e.g., fluvoxamine): Potentially large increase in tasimelteon exposure and greater risk of adverse reactions. Avoid use of tasimelteon in combination with fluvoxamine or other strong CYP1A2 inhibitors.
  • Strong CYP3A4 inducers (e.g., rifampin): Potentially large decrease in tasimelteon exposure with reduced efficacy. Avoid use of tasimelteon in combination with rifampin or other CYP3A4 inducers.
  • 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 may reduce the efficacy of tasimelteon.
Read the label’s full interactions text

7 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.

Read the full Drug Interactions section on DailyMed →

Not a complete list. The label covers the interactions the manufacturer studied or reported, and our own interaction database does not cover every medicine either. Bring your full medication list, including vitamins and herbal products, to your pharmacist.

🌿218 supplements and herbs with documented Tasimelteon interactions, ranked by severity Check Tasimelteon against a supplement or herb →

Before taking Tasimelteon

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  • Severe liver disease: Hetlioz is not recommended if you have severe hepatic impairment (Child-Pugh Class C).
  • Older adults (over 65): Drug exposure is roughly doubled compared to younger adults — your doctor should be aware so they can monitor you closely.
  • Smokers: Tasimelteon may be less effective; let your prescriber know you smoke.
  • Pregnancy: Human safety data in pregnancy are very limited; animal studies showed fetal harm at high doses. Discuss the risks and benefits with your doctor.
  • Breastfeeding: It is not known whether tasimelteon passes into breast milk. Talk to your doctor before breastfeeding while taking this medication.
  • Children under 3: Safety and effectiveness in children younger than 3 years have not been established.
  • Hetlioz capsules vs. Hetlioz LQ oral suspension: These two forms are not interchangeable — always use the specific product your prescriber ordered.

Tasimelteon overdose

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There is limited information about what happens with a tasimelteon overdose. If an overdose is suspected, call Poison Control right away for guidance. General supportive care — monitoring vital signs and providing fluids as needed — is the main approach.

What Tasimelteon does in the body

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Tasimelteon binds to and activates melatonin MT1 and MT2 receptors, with a stronger attraction to MT2. These receptors are thought to be involved in regulating the body's circadian rhythm — its internal 24-hour timing system. The drug's main metabolites (breakdown products) have much weaker activity at these receptors than tasimelteon itself.

How your body processes Tasimelteon

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After an oral dose taken on an empty stomach, tasimelteon capsules reach peak blood levels within about 30 minutes to 3 hours; the oral suspension reaches peak levels faster, within about 15 to 30 minutes. The drug is extensively broken down by liver enzymes (mainly CYP1A2 and CYP3A4) and has a short elimination half-life of roughly 1.3 hours, meaning it clears from the body relatively quickly. About 80% of the drug is excreted in the urine. Taking tasimelteon with food — especially a high-fat meal — significantly lowers the peak drug level and delays absorption, which is why it should always be taken on an empty stomach.

How to store Tasimelteon

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Store HETLIOZ capsules at controlled room temperature, 20°C to 25°C (68°F to 77°F); excursions permitted to 15°C to 30°C (59°F to 86°F) . Protect from exposure to light and moisture.

Written from the FDA-approved label with AI and reviewed by our pharmacy team. How we use AI →

218

Supplements & herbs that interact with Tasimelteon

218 supplements and herbal products have documented interactions with Tasimelteon in the licensed clinical database we use. Most are manageable — but your pharmacist should know about everything you take, including vitamins and herbals.

Severity mix
  • Major · 9
  • Moderate · 166
  • Minor · 43
1,4-BUTANEDIOL Major ACTIVATED CHARCOAL Major BEER Major GAMMA-HYDROXYBUTYRATE (GHB) Major GRAPEFRUIT Major KAVA Major L-TRYPTOPHAN Major ST. JOHN'S WORT Major +210 more
Every supplement checked against Tasimelteon — ranked by severity The full interaction hub: 9 major · 166 moderate · 43 minor · every one linked to its full report. Check Tasimelteon against your exact supplements

Educational information from a licensed clinical database (Natural Medicines) — see our data sources & update cadence. Not medical advice: an interaction being documented does not mean it will happen to you; do not start or stop medications or supplements without professional guidance.

Tasimelteon: pharmacist answers to common questions

Quick, plain-English answers to the questions patients ask most about Tasimelteon — the kind of thing our pharmacy team would talk through with you at the counter.

How long will it take before I actually start sleeping better?

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That's a really common question, and the honest answer is: it varies. Because everyone's internal body clock runs a little differently, some people notice improvement within a few weeks, but for others it can take several months of taking it every night. The key is consistency — take it at the same time each night, on an empty stomach. Don't give up too early; this isn't a medication that works overnight in the way a typical sleep aid might.

Can I eat dinner before taking this?

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You'll want to time your meal carefully. Eating — especially a high-fat meal — can significantly reduce how much tasimelteon your body actually absorbs, and it delays how quickly the drug starts working. The recommendation is to take it without food, about one hour before bed. A light snack much earlier in the evening should be fine, but avoid eating right before your dose.

Will this make me feel groggy or out of it the next morning?

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Drowsiness is a known effect of tasimelteon, which is actually intentional — it's helping shift your sleep timing. The main advice is to take it and then head straight to bed; don't drive or do anything that needs sharp focus after your dose. Most people find that as long as they go to bed after taking it, morning grogginess isn't a major issue, but everyone is different. If you find it's affecting you the next day, let your doctor know.

Are there any medications I need to avoid while taking this?

▾
Yes, a couple of important ones. Fluvoxamine and similar strong CYP1A2 inhibitors can cause tasimelteon to build up to much higher levels in your blood, which raises the risk of side effects — so that combination should be avoided. On the flip side, rifampin and similar drugs can speed up the breakdown of tasimelteon and make it less effective. Also, if you take a beta-blocker (a blood pressure or heart rate medication) at night, it may reduce tasimelteon's effectiveness. Always give your pharmacist and doctor a full list of your medications.

I smoke — does that affect how well this medication works?

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It can, yes. Smoking triggers an enzyme in your body that breaks down tasimelteon faster than normal, which means smokers tend to have lower blood levels of the drug. That could mean it works less well for you. Make sure your prescriber knows you smoke so they can factor that in when deciding on your treatment plan.

Is it safe to take if I'm pregnant or breastfeeding?

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This is definitely a conversation to have with your doctor. There isn't enough human data yet to say it's fully safe during pregnancy, and animal studies at high doses did show some concerns. For breastfeeding, we simply don't know yet whether the drug passes into breast milk. Your doctor can help you weigh the benefits of treating your sleep disorder against any potential risks, so please don't stop or start anything without talking to them first.

Is Tasimelteon available over the counter?

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No. Tasimelteon is a prescription medicine: every Tasimelteon product listed with the FDA is prescription only, so it is not sold over the counter. Your prescriber decides whether it is appropriate for you, and your pharmacist dispenses it.

When was Tasimelteon first available?

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The earliest FDA record we hold for Tasimelteon is from 2014: its first approval in Drugs@FDA or its earliest product listing in the NDC Directory, whichever is older. Many older medicines were in use before their first formal FDA approval, so this is the earliest date on record, not necessarily when Tasimelteon was first used.

Who makes Tasimelteon?

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4 companies currently list Tasimelteon products in the FDA's NDC Directory, including Vanda Pharmaceuticals Inc., Amneal Pharmaceuticals NY LLC, Apotex Corp.. That count includes repackagers and distributors as well as manufacturers (companies that sell only the raw ingredient are not counted), so fewer companies actually make it; the label on your bottle names the one that supplied yours.

Answers drafted from the FDA-approved label with AI and reviewed by our pharmacy team. How we use AI →

More about Tasimelteon on HelloPharmacist

📊Tasimelteon supplement interactions218 checked — ranked by severity 🌿Drug & Supplement CheckerTasimelteon vs. vitamins & herbs 💬Ask a PharmacistFree answer, usually < 24h 🔎NDC & pricing lookupFind Tasimelteon NDCs & costs 🅰️Browse Drugs A–ZLook up any medication
Detailed data & references for Tasimelteon Forms & strengths, pricing, billing codes, manufacturers, safety reports and sourcing — the data behind the page. Most people can stop here. Each section below opens on a tap.

Tasimelteon forms and strengths (how it comes)

Tasimelteon is available in 2 forms. Different forms and brands can have different approved uses, doses, schedules, and directions. Follow the instructions for your exact product, and do not switch forms without guidance from your prescriber or pharmacist.

Need a version that does not list lactose, a gluten source, a dye or gelatin? Inactive ingredients differ by manufacturer: see Tasimelteon inactive ingredients by manufacturer.

Capsule

By mouth
Brands Hetlioz
How this form is used
What it may be used for
  • Hetlioz capsules are approved to treat Non-24-Hour Sleep-Wake Disorder in adults
  • Hetlioz capsules are approved to treat nighttime sleep disturbances in Smith-Magenis Syndrome in patients 16 years of age and older
  • Tasimelteon capsules are approved to treat Non-24-Hour Sleep-Wake Disorder in adults
Important instructions
  • Take one capsule by mouth about one hour before bedtime, at the same time every night
  • Always take on an empty stomach — food significantly lowers absorption
  • If you cannot take it at your usual time on a given night, skip that dose and resume the next night as scheduled
  • Hetlioz capsules and Hetlioz LQ oral suspension are not interchangeable — do not substitute
Available strengths 1 strength
20 mg
13 FDA-listed product records ⓘ

Oral suspension

By mouth
Brands Hetlioz
How this form is used
What it may be used for
  • Hetlioz LQ oral suspension is approved to treat nighttime sleep disturbances in Smith-Magenis Syndrome in pediatric patients ages 3 to 15 years
Important instructions
  • Hetlioz LQ oral suspension should be given by mouth about one hour before bedtime, at the same time every night
  • Always give on an empty stomach — food significantly lowers absorption
  • Shake Hetlioz LQ oral suspension well for at least 30 seconds before every dose; use the press-in bottle adapter and oral syringe included in the package
  • Store refrigerated; after opening, discard after 5 weeks (48 mL bottle) or 8 weeks (158 mL bottle)
Available strengths 1 strength
4 mg/mL
3 FDA-listed product records ⓘ

Tasimelteon on the U.S. market: products, makers and brands

How Tasimelteon appears in the FDA’s National Drug Code Directory — including its dosage forms, strengths, brand names, manufacturers, and FDA-listed product records. These are directory records, not sales or prescription volume.

4 companies list 5 Tasimelteon product records with the FDA, mostly as capsule, oral suspension; the earliest marketing or approval year on record is 2014. Brand names on the directory include Hetlioz, Hetlioz LQ; the rest are generics.

2
Dose forms ⓘ
4
Labelers (makers, repackagers, distributors)
3
Brand names
5
FDA-listed product records ⓘ
2014
Earliest FDA record ⓘ

FDA-listed product records by dose form (tablet variants merged) — FDA National Drug Code Directory. Record counts are not sales or prescription volume.

Also listed with the FDA, not a patient dose form: Powder (5) — bulk drug substance sold to compounders/manufacturers and multi-item kits. These aren’t counted in the dose-form total above.

Vanda Pharmaceuticals Inc.40%
Amneal Pharmaceuticals NY LLC20%
Apotex Corp.20%
Teva Pharmaceuticals, Inc.20%

Share of FDA-listed product records by manufacturer — FDA National Drug Code Directory. Record counts are not sales or prescription volume.

How widely Tasimelteon is used (Medicaid data)

A general measure of how commonly Tasimelteon is prescribed, based on Medicaid — one of the largest public drug programs. The figure below is prescriptions filled in Q1–Q4 2025, summed across every form and brand of the drug.

Think of this as a proxy for how widely Tasimelteon is used, drawn from freely available public data. Medicaid is just one program — these numbers don’t include Medicare, other government coverage, or commercial and cash-pay prescriptions, so real-world use is higher than what’s shown here.

1,179
Medicaid prescriptions filled (Q1–Q4 2025)
$21.6M gross Medicaid reimbursement (before mandatory rebates — net cost is lower)

How commonly is Tasimelteon prescribed? Of the 1,601 medications we measure, Tasimelteon ranks #1,264 by Medicaid prescriptions — more than 21% of them.

Where Tasimelteon ranks among the drugs we measure · Q1–Q4 2025 · neighbors ±5
Total prescriptions — #1,264 of 1,601
#1,259 Droxidopa 1,239 Rx #1,260 Diethylpropion 1,227 Rx #1,261 Amiloride and Hydrochl... 1,216 Rx #1,262 Lurbinectedin Injectio... 1,194 Rx #1,263 Donepezil / Memantine 1,194 Rx #1,264 Tasimelteon 1,179 Rx #1,265 Maralixibat 1,179 Rx #1,266 Amphotericin B Injecti... 1,153 Rx #1,267 Vismodegib 1,149 Rx #1,268 Cefiderocol Injection 1,141 Rx #1,269 Anagrelide 1,137 Rx

Utilization by Tasimelteon product

Pick a product to see its own Medicaid numbers. Each chip is one clinical product — a specific strength & dosage form as defined by RxNorm — with brand-name and generic versions combined.

The 20 mg oral capsule is the most-dispensed Tasimelteon product — about 97% of these Medicaid prescriptions.

tasimelteon 20 MG Oral Capsule Most dispensed

1,143 Medicaid prescriptions (Q1–Q4 2025) 97% of Tasimelteon prescriptions shown $20.7M gross reimbursement (before rebates) ≈ $18,100 per prescription (gross)

Summed across the 4 of 7 listed NDC products with Medicaid activity — every brand and generic of this exact strength & form. RxNorm 1490473

tasimelteon 4 MG/ML Oral Suspension

36 Medicaid prescriptions (Q1–Q4 2025) 3% of Tasimelteon prescriptions shown $903,203 gross reimbursement (before rebates) ≈ $25,089 per prescription (gross)

Summed across the 1 of 2 listed NDC products with Medicaid activity — every brand and generic of this exact strength & form. RxNorm 2468312

Shares are of the Medicaid prescriptions shown here. Product grouping follows RxNorm (the National Library of Medicine’s drug terminology), so “one product” means one strength & dosage form regardless of manufacturer. Dollar figures are gross Medicaid reimbursement before mandatory rebates — rebates (often large, especially for brand-name drugs) are confidential, so actual net cost to Medicaid is lower than shown.

Source: Medicaid State Drug Utilization Data (CMS), aggregated by generic ingredient — summed across every NDC (all brands, strengths, salt forms and dosage forms) of Tasimelteon, and across all states and both fee-for-service and managed-care claims. A general popularity signal; it excludes Medicare, commercial insurance and cash prescriptions, so it is not total U.S. use. Based on the 5 of 9 listed Tasimelteon NDCs with Medicaid activity.

Compare Tasimelteon products

A representative set of FDA-listed product records for Tasimelteon — across manufacturers, strengths, and dosage forms, grouped by form with each product’s manufacturer and how the FDA approved it. The same medicine may be made and packaged by different companies, so a single drug can have many directory entries. (It’s also why a refill can look different — a new shape, color, or box — even though it contains the same medication.)

Strength Route Manufacturer / Labeler Category ⓘ Details
💊Capsule
20 mg Oral Amneal Pharmaceuticals NY LLC ANDA View NDC →
20 mg Oral Apotex Corp. ANDA View NDC →
20 mg Oral Teva Pharmaceuticals, Inc. ANDA View NDC →
20 mg Oral Vanda Pharmaceuticals Inc. NDA View NDC →
💊Oral suspension
4 mg/mL Oral Vanda Pharmaceuticals Inc. NDA View NDC →

Showing 5 of 5 products — FDA National Drug Code Directory. See every product, package size and price: browse all 5 Tasimelteon NDCs →

Tasimelteon recall history

A recall is when a specific batch of a medicine is pulled from the market — usually a manufacturing issue, not a problem with the drug itself. Class I is most serious, Class III least.

The FDA’s enforcement reports list no Tasimelteon recalls since July 2021.

✅No Tasimelteon recalls on record since July 2021

Source: FDA enforcement (recall) reports, via openFDA; our copy was last updated Sep 24, 2026.

RxNorm Concept Web — From Ingredient to Every Form and Strength

This page starts with one ingredient concept (IN). The branches below show its dose-form concepts (SCDF), then the available clinical drug and strength concepts (SCD). Combination products remain separate concepts with their own pages.

Ingredient (IN) Tasimelteon RxCUI 1490468 2 dose forms · 2 strengths
  1. Dose form (SCDF) Oral Capsule RxCUI 1490472 In current FDA listings
    Clinical drug / strength (SCD) 20 MG RxCUI 1490473
  2. Dose form (SCDF) Oral Suspension RxCUI 2468311 In current FDA listings
    Clinical drug / strength (SCD) 4 MG/ML RxCUI 2468312

Look up RxCUI 1490468 in the RxCUI Atlas →

RxNorm is the U.S. National Library of Medicine’s normalized drug vocabulary. Its concept hierarchy can include forms that are not currently marketed; the status on each branch compares that concept with current FDA listings. RxCUIs identify vocabulary concepts, not individual packages or manufacturers.

💵 What Tasimelteon costs pharmacies (NADAC benchmark)

The national average invoice price pharmacies pay for the drug itself, from CMS's NADAC survey (data as of Sep 30, 2026). This is a supply-cost benchmark — not a retail price and not what you'd pay at the counter.

FormStrengthPharmacy acquisition benchmark
Capsule, Gelatin Coated · Oral 20 mg $228.25 per capsule NDC details & price history
Capsule, Gelatin Coated 20 mg $228.25 per capsule NDC details & price history
Why show this? Your out-of-pocket cost depends on insurance, pharmacy markup, and discounts — but the acquisition benchmark tells you whether the medication itself is inexpensive or costly, which strengths cost more per dose, and whether a cash-price quote is in a reasonable range. Each row links to the NDC-level record with its full price history.

Source: CMS National Average Drug Acquisition Cost (NADAC), a survey of retail pharmacy invoice prices. Benchmarks shown are the range across package sizes of a representative product for each form and strength — other manufacturers' products may differ.

Tasimelteon brand names

Tasimelteon is sold under 2 brand names in the FDA directory — Hetlioz, Hetlioz LQ. A brand and its generic contain the same active ingredient; the brand name belongs to one company's product.

Hetlioz Hetlioz LQ

Who makes Tasimelteon: manufacturers and labelers

4 companies list Tasimelteon products with the FDA. By number of product records, the largest are Vanda Pharmaceuticals Inc., Amneal Pharmaceuticals NY LLC, Apotex Corp.. Labelers include manufacturers and repackagers; the product in your bottle depends on which one your pharmacy stocks.

Vanda Pharmaceuticals Inc. 2 Amneal Pharmaceuticals NY LLC 1 Apotex Corp. 1 Teva Pharmaceuticals, Inc. 1

Tasimelteon drug class (RxNorm)

Tasimelteon belongs to the Melatonin Receptor Agonist class.

Pharmacologic class Melatonin Receptor Agonist
Drug family (ATC) Melatonin receptor agonists
How it works Melatonin Receptor Agonists

Classified by RxNorm RxClass — the U.S. National Library of Medicine's standardized drug-classification service (Established Pharmacologic Class from the FDA, the ATC drug family from the WHO, and mechanism of action). Reference only, not medical advice.

Sources for this Tasimelteon page

Core label, product, RxNorm, safety, and utilization data on this page come from the sources identified below. AI-written, editorial, and licensed sections are labeled separately.

📄
FDA-filed drug labels (SPL) Uses, dosing, warnings & side effects from SPL records retrieved through openFDA; the linked representative set can be verified on DailyMed. ✓ Linked label effective Aug 4, 2026
🏭
Forms, brands & labelersAggregated from ingredient-matched FDA National Drug Code Directory product records for Tasimelteon.
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Real-world reportsThe FDA Adverse Event Reporting System (FAERS), served through openFDA.
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Recalls & shortagesopenFDA drug-enforcement reports and the FDA drug-shortage database.
🧾 Clinical label set — FDA-filed SPL labels retained for Tasimelteon after exact ingredient or ingredient-combination matching and applicable route/form matching
Clinical labels in scope
4
Finished products in the current FDA directory
5
Companies listing them (makers, repackagers, distributors)
4
FDA labeler codes behind them ⓘ
4
Linked representative label ⓘ
Vanda Pharmaceuticals Inc.
Linked label effective
Aug 4, 2026
Composite sections available
26
Linked SPL Set ID
ca4a9b63-708e-49e9-8f9b-010625443b90
Linked SPL Document ID
8463c372-11ff-4caf-ad72-54d54a4a795d
Open the linked representative label on DailyMed ↗

How this page is built

HelloPharmacist combines public FDA and NLM records and does not author the underlying clinical facts. The plain-language sections are written with AI from the FDA-approved label text and reviewed by our pharmacy team before publication. Vanda Pharmaceuticals Inc. is the representative DailyMed label linked for verification and dates. This is general education, not medical advice: always talk to your doctor or pharmacist about your own medicines. How we build and review drug pages →