Skip to Content
Living with relapsing MS? Don’t miss these free events >>

Tasimelteon

Generic Name: tasimelteon (TAS-i-MEL-tee-on)
Brand Name: Hetlioz

Tasimelteon is used for:

Treating a certain type of sleep problem called Non-24-Hour Sleep-Wake Disorder (Non-24).

Tasimelteon is a melatonin agonist. Exactly how it works is not known. It acts on the melatonin receptors in the brain to help regulate the body's sleep cycle.

Do NOT use tasimelteon if:

  • you are allergic to any ingredient in tasimelteon
  • you have severe liver problems
  • you are taking fluvoxamine or rifampin

Contact your doctor or health care provider right away if any of these apply to you.

Before using tasimelteon:

Some medical conditions may interact with tasimelteon. Tell your doctor or pharmacist if you have any medical conditions, especially if any of the following apply to you:

  • if you are pregnant, planning to become pregnant, or are breast-feeding
  • if you are taking any prescription or nonprescription medicine, herbal preparation, or dietary supplement
  • if you have allergies to medicines, foods, or other substances
  • if you have liver problems
  • if you smoke

Some MEDICINES MAY INTERACT with tasimelteon. Tell your health care provider if you are taking any other medicines, especially any of the following:

  • Fluvoxamine or ketoconazole because they may increase the risk of tasimelteon's side effects
  • Rifampin because it may decrease tasimelteon's effectiveness

This may not be a complete list of all interactions that may occur. Ask your health care provider if tasimelteon may interact with other medicines that you take. Check with your health care provider before you start, stop, or change the dose of any medicine.

How to use tasimelteon:

Use tasimelteon as directed by your doctor. Check the label on the medicine for exact dosing instructions.

  • Take tasimelteon by mouth without food.
  • Take tasimelteon before bedtime at the same time each night.
  • Swallow tasimelteon whole. Do not break, crush, or chew before swallowing.
  • After you take tasimelteon, limit your activities to those necessary to prepare for bed.
  • If you miss a dose of tasimelteon, skip the missed dose. Do not take the dose in the morning or take 2 doses at once.

Ask your health care provider any questions you may have about how to use tasimelteon.

Important safety information:

  • Tasimelteon may cause drowsiness. These effects may be worse if you take it with alcohol or certain medicines. Use tasimelteon with caution. Do not drive or perform other possibly unsafe tasks until you know how you react to it.
  • Check with your doctor before you drink alcohol or use medicines that may cause drowsiness (eg, sleep aids, muscle relaxers) while you are taking tasimelteon; it may add to their effects. Ask your pharmacist if you have questions about which medicines may cause drowsiness.
  • Tasimelteon may take several weeks or months to work. Do NOT take more than the recommended dose or use for longer than prescribed without checking with your doctor.
  • Use tasimelteon with caution in the ELDERLY; they may be more sensitive to its effects.
  • Tasimelteon should be used with extreme caution in CHILDREN; safety and effectiveness in children have not been confirmed.
  • PREGNANCY and BREAST-FEEDING: If you become pregnant, contact your doctor. You will need to discuss the benefits and risks of taking tasimelteon while you are pregnant. It is not known if this medicine is found in breast milk. If you are or will be breast-feeding while you take tasimelteon, check with your doctor. Discuss any possible risks to your baby.

Possible side effects of tasimelteon:

All medicines may cause side effects, but many people have no, or minor, side effects. Check with your doctor if any of these most COMMON side effects persist or become bothersome:

Cough; headache; nightmares or unusual dreams; runny or stuffy nose; sneezing; sore throat.

Seek medical attention right away if any of these SEVERE side effects occur:

Severe allergic reactions (rash; hives; itching; difficulty breathing; tightness in the chest; swelling of the hands, legs, mouth, face, lips, eyes, or tongue); difficult or painful urination.

This is not a complete list of all side effects that may occur. If you have questions about side effects, contact your health care provider. Call your doctor for medical advice about side effects. To report side effects to the appropriate agency, please read the Guide to Reporting Problems to FDA.

If OVERDOSE is suspected:

Contact 1-800-222-1222 (the American Association of Poison Control Centers), your local poison control center, or emergency room immediately.

Proper storage of tasimelteon:

Store tasimelteon at 77 degrees F (25 degrees C). Brief storage at temperatures between 59 and 86 degrees F (15 and 30 degrees C) is permitted. Store away from heat, moisture, and light. Do not store in the bathroom. Keep tasimelteon out of the reach of children and away from pets.

General information:

  • If you have any questions about tasimelteon, please talk with your doctor, pharmacist, or other health care provider.
  • Tasimelteon is to be used only by the patient for whom it is prescribed. Do not share it with other people.
  • If your symptoms do not improve or if they become worse, check with your doctor.
  • Check with your pharmacist about how to dispose of unused medicine.

This information should not be used to decide whether or not to take tasimelteon or any other medicine. Only your health care provider has the knowledge and training to decide which medicines are right for you. This information does not endorse any medicine as safe, effective, or approved for treating any patient or health condition. This is only a brief summary of general information about tasimelteon. It does NOT include all information about the possible uses, directions, warnings, precautions, interactions, adverse effects, or risks that may apply to tasimelteon. This information is not specific medical advice and does not replace information you receive from your health care provider. You must talk with your health care provider for complete information about the risks and benefits of using tasimelteon.

Review Date: November 3, 2016

Disclaimer: This information should not be used to decide whether or not to take this medicine or any other medicine. Only your health care provider has the knowledge and training to decide which medicines are right for you. This information does not endorse any medicine as safe, effective, or approved for treating any patient or health condition. This is only a brief summary of general information about this medicine. It does NOT include all information about the possible uses, directions, warnings, precautions, interactions, adverse effects, or risks that may apply to this medicine. This information is not specific medical advice and does not replace information you receive from your health care provider. You must talk with your healthcare provider for complete information about the risks and benefits of using this medicine.

Hide