tasimelteon
Tasimelteon (Hetlioz) is a prescription medication that treats specific sleep problems, including non-24-hour sleep-wake disorder (non-24) in adults and sleep disturbances in both children and adults with Smith-Magenis Syndrome (SMS). It comes as capsules for adults and a liquid suspension for children. The dosage is typically taken by mouth at the same time every night, about 1 hour before bed. Tasimelteon (Hetlioz) can potentially interact with many medications. Common side effects include headache and nightmares or unusual dreams.
What is Tasimelteon (Hetlioz)?
What is Tasimelteon (Hetlioz) used for?
Non-24-hour sleep-wake disorder (non-24) in adults
Nighttime sleep disturbances in children and adults with Smith-Magenis Syndrome (SMS)
How Tasimelteon (Hetlioz) works
Tasimelteon (Hetlioz) is a melatonin receptor agonist, meaning it acts like melatonin. Melatonin is a natural hormone your body makes when it’s dark to help maintain a normal sleep cycle.
It’s not fully known how tasimelteon (Hetlioz) works, but it’s believed to help regulate sleep by working like melatonin, helping you sleep at night and stay alert during the day.
Drug Facts
Get your GoodRx coupon
What are the side effects of Tasimelteon (Hetlioz)?
Common Side Effects
- Headache (17%)
- Abnormal liver tests (10%)
- Nightmares or unusual dreams (10%)
Other Side Effects
- Upper respiratory tract infection
- Urinary tract infection
Source: DailyMed
The following side effects have also been reported
Side effects that you should report to your care team as soon as possible:
- Allergic reactions—skin rash, itching, hives, swelling of the face, lips, tongue, or throat
Side effects that usually do not require medical attention (report to your care team if they continue or are bothersome):
- Headache
- Vivid dreams or nightmares
Pros and cons of Tasimelteon (Hetlioz)
Pros
Only FDA-approved medication to help people with non-24 and SMS maintain a regular sleep cycle
Not a controlled substance so it's not habit forming
Available as a liquid suspension for children with SMS
Cons
Can take weeks to months for you to notice any effect
Must be taken at the same time every night
Interacts with many medications, such as rifampin, fluvoxamine, and metoprolol
Pharmacist tips for Tasimelteon (Hetlioz)
Take tasimelteon (Hetlioz) at the same time every night to maintain a regular sleep cycle. If you can't take it at the usual time one night, skip that dose and take the next one at your regular time the following night. This way, the medication can keep working properly.
Take tasimelteon (Hetlioz) on an empty stomach 1 hour before bedtime. This helps your body absorb the medication faster so that you can fall asleep sooner. Taking it with food can reduce how much medication your body absorbs and potentially delay when it starts working.
Once you take tasimelteon (Hetlioz), focus only on preparing for bed. The medication might affect your ability to stay fully alert, so avoid doing anything that needs full concentration.
Tasimelteon (Hetlioz) works to correct sleep rhythm gradually. It can take weeks or months before you notice any improvements in your sleep. Continue taking the medication unless your prescriber says otherwise.
If you smoke tobacco, tasimelteon (Hetlioz) might not work as well because smoking can reduce the amount of medication in your body. Speak with your prescriber if you have questions about quitting smoking.
Keep tasimelteon (Hetlioz) capsules at room temperature, away from light and moisture. Store Hetlioz LQ liquid suspension in the refrigerator.
Tips for Hetlioz LQ liquid suspension:
Shake the bottle well for at least 30 seconds before each use. If it’s your first time using the bottle, take off the seal and press the provided adapter into the neck of the bottle until it’s even with the top of the bottle. Once the adapter is attached, don’t remove it.
After attaching the adapter, shake the bottle again. Turn it upside down and use the provided syringe to measure the prescribed dose. When finished, leave the adapter on, replace the cap, and store the bottle in the refrigerator.
Write the date you open the bottle. Throw out the 48-mL bottle after 5 weeks and the 158-mL bottle after 8 weeks, even if there’s leftover medication.
Frequently asked questions about Tasimelteon (Hetlioz)
How to save using GoodRx
What are the risks and warnings for Tasimelteon (Hetlioz)?
Tasimelteon (Hetlioz) can cause some serious health issues. This risk may be even higher for certain groups. If this worries you, talk to your doctor or pharmacist about other options.
Sleepiness
Tasimelteon (Hetlioz) helps you sleep. After taking it, focus only on getting ready for bed since it can make it harder to do activities that require you to be fully alert.
Interactions with other medications
Some medications can change how your body gets rid of tasimelteon (Hetlioz). For example, fluvoxamine (Luvox) and ciprofloxacin (Cipro) can raise its levels, which can lead to more side effects. On the other hand, rifampin (Rifadin) and phenytoin (Dilantin) can lower its levels, making it work less. Let your prescriber or pharmacist know about all medications you’re taking to make sure they’re safe with tasimelteon (Hetlioz).
Tasimelteon (Hetlioz) dosage forms
| Dosage | Quantity | Price as low as | Price per unit |
|---|---|---|---|
| 20mg | 30 capsules | $5895.21 | $196.51 |
Typical dosing for Tasimelteon (Hetlioz)
Non-24: The typical dose is one 20 mg capsule, taken by mouth 1 hour before bedtime on an empty stomach.
Nighttime sleep disturbances in SMS:
People ages 16 and older: The typical dose is one 20 mg capsule, taken by mouth 1 hour before bedtime on an empty stomach.
Children ages 3 to 15: Your child's dose of the liquid suspension (Hetlioz LQ) will depend on their weight.
Weighing less than 62 lbs (28 kg): The typical dose is 0.7 mg/kg by mouth 1 hour before bedtime on an empty stomach.
Weighing 62 lbs (28 kg) or more: The typical dose is 20 mg (5 mL) by mouth 1 hour before bedtime on an empty stomach.
Note: The capsules and liquid suspension are NOT interchangeable.
How much does Tasimelteon (Hetlioz) cost?
Tasimelteon (Hetlioz) images
Get savings updates for Tasimelteon (Hetlioz)
Receive price alerts, news, and other messages from GoodRx about Tasimelteon (Hetlioz) and other healthcare topics and relevant savings offers.By providing your email, you consent to receive marketing communications from GoodRx, which may include content and/or data related to men’s health, women's health, reproductive care, or sexual health. You agree to the GoodRx Terms of Use and acknowledge the Privacy Policy. You can unsubscribe at any time.
References
Best studies we foundLockley, S. W., et al. (2015). Tasimelteon for non-24-hour sleep-wake disorder in totally blind people (SET and RESET): Two multicentre, randomised, double-masked, placebo-controlled phase 3 trials. The Lancet.
National Organization for Rare Disorders. (2017). Non-24-hour sleep-wake disorder.
National Organization for Rare Disorders. (2024). Smith-Magenis syndrome.
Polymeropoulos, C. M., et al. (2021). Tasimelteon safely and effectively improves sleep in Smith-Magenis syndrome: A double-blind randomized trial followed by an open-label extension. Genetics in Medicine.
Vanda Pharmaceuticals Inc. (2022). Hetlioz- tasimelteon capsule; Hetlioz LQ- tasimelteon suspension [package insert]. DailyMed.
Compare other Insomnia drugs
Browse medications
View AllResearch prescriptions and over-the-counter medications from A to Z, compare drug prices, and start saving.