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tasimelteon

Hetlioz · ATC code N05CH

Key facts
Active substance
tasimelteon
Drug class
Melatonin receptor agonist
ATC code
N05CH
Authorisation
centrally authorised across the EU (EMA)
Dosage forms
HETLIOZ 20 mg hard capsules
Marketing authorisation holder
Vanda Pharmaceuticals Netherlands B.V.
Information as of
2026-10-28

Key facts

Tasimelteon is a melatonin receptor agonist that acts as a circadian regulator, used to treat Non-24-Hour Sleep-Wake Disorder in totally blind adults (Hetlioz).

What it is used for

  • Treatment of Non-24-Hour Sleep-Wake Disorder (Non-24) in totally blind adults.

Dosing

  • Hetlioz: 20 mg (1 capsule) per day taken one hour before bedtime, at the same time every night; intended for chronic use.
  • Take without food; after a high-fat meal wait at least 2 hours. Swallow capsules whole.
  • No dose adjustment in the elderly, renal impairment, or mild to moderate hepatic impairment; caution in severe hepatic impairment.
  • Response should be evaluated 3 months after starting treatment.

Contraindications

  • Hypersensitivity to the active substance or any excipient.

Important warnings

  • After taking tasimelteon, activity should be limited to preparing for bed.
  • Caution with fluvoxamine or other strong CYP1A2 inhibitors (large increase in exposure) and with CYP3A4 inducers such as rifampin (reduced efficacy).
  • Contains lactose and the azo colouring agent Orange Yellow S (E110), which may cause allergic reactions.

Side effects

  • Most common (>3%): headache (10.4%), somnolence (8.6%), nausea (4.0%) and dizziness (3.1%), mostly mild to moderate and transient.
  • Also common: sleep disorder, insomnia, abnormal dreams, dyspepsia, dry mouth, fatigue; uncommon: nightmare, dysgeusia, tinnitus, pollakiuria.

Interactions

  • Strong CYP1A2 inhibitors (e.g. fluvoxamine, ciprofloxacin, enoxacin) greatly increase tasimelteon exposure; use with caution.
  • Strong CYP3A4 inhibitors (e.g. ketoconazole) increase exposure by approximately 50%; avoid rifampin and other CYP3A4 inducers.
  • Smoking decreases exposure by approximately 40%; beta blockers may reduce efficacy.

Pregnancy and breastfeeding

  • As a precaution, avoid use during pregnancy.
  • Breast-feeding: decide between stopping breast-feeding or therapy based on benefit and risk.

Summary of the official product information, written with AI on 2026-10-29. Every number was checked automatically against the original text. Not reviewed by a physician – the full official text is authoritative.

Full official text →

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For patients

Package leaflet, verbatim

This product has no separate US patient information.

Authorisation and brand names by country

Medicines with exactly this active-substance composition, as listed in the national registers – alphabetical and without ranking. Whether a product is currently available is not shown here.

EU – centrally authorised (all member states)

  • HetliozVanda Pharmaceuticals Netherlands B.V. · EMEA/H/C/003870

Source: European Medicines Agency (EMA), product information

Brand names in 3 more European countries
Iceland
Hetlioz
Liechtenstein
Hetlioz
Norway
Hetlioz

EMA – Article 57 product data (EU/EEA), 2026-10-29

Medelix receives no money from pharmaceutical companies. Brand names are listed alphabetically and without ranking.

Other substances in the same group

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Sources

  1. European Medicines Agency. Hetlioz – EPAR, Product Information. 2026-10-28. https://www.ema.europa.eu/en/documents/product-information/hetlioz-epar-product-information_en.pdf
  2. Wikidata (CC0): ATC N05CH.

Editorial: Medelix editorial team · last updated 2026-10-28 · How these pages are made · Report an error

Source: European Medicines Agency (EMA), product information. Not advertising, not a treatment recommendation. For questions about your own treatment, ask your doctor or pharmacist.