Jeffrey Panko NP Psychiatry · Patient education
Tasimelteon
Hetlioz / Adult capsules
A guide for adults taking tasimelteon.
Follow the directions on your prescription and your provider's recommendations.
Formulations: Adult treatment uses capsules. The pediatric oral suspension has separate instructions and is not substitutable for capsules.
What it is used for
Tasimelteon treats Non-24-Hour Sleep-Wake Disorder in adults and nighttime sleep disturbance in Smith-Magenis syndrome under age- and formulation-specific labeling. It is not a general substitute for an insomnia medicine.
How it works
It activates melatonin receptors involved in circadian timing. Consistent timing helps align treatment with the intended sleep–wake schedule.
What to expect over time
For Non-24, improvement in sleep timing may take weeks or months. Keep a sleep diary and continue scheduled follow-up rather than taking extra doses for immediate sedation.
Taking your medication
- Take one hour before bedtime, at the same time each night, without food.
- Swallow capsules whole.
- If you cannot take it near the usual time, skip that night and resume the next scheduled dose. Do not double.
- After dosing, limit activity to preparing for bed.
When to get help
Emergency symptoms. Call 911 for severe breathing difficulty, inability to wake, collapse, or severe allergy.
Prompt medical advice. Report marked daytime sedation, falls, or new unsafe behavior promptly.
If you feel unsafe or have thoughts of self-harm, call 911 or go to an emergency department.
Possible side effects
- Headache or sleepiness
- Unusual dreams or nightmares
- Possible next-day impairment
Keeping track of treatment
Some side effects resolve with time; others may require a change of medication. Discuss persistent or bothersome side effects with your provider.
Track sleep timing, naps, alertness, and falls. Report persistent daytime sleepiness or symptoms that suggest another sleep disorder.
If you take too much
For a suspected overdose, call Poison Control at 1-800-222-1222 immediately, even if you feel well. Call 911 for a seizure, collapse, trouble breathing, or inability to wake.
Before you start
Discuss liver disease, smoking changes, other sleep conditions, and responsibilities requiring overnight alertness.
Discuss pregnancy, pregnancy plans, and breastfeeding with your provider. Treatment decisions should consider both the medication and the condition being treated.
Medicines and interactions
Review all your medications with your provider, including over-the-counter medicines and supplements. Have new medications checked before taking them.
Strong CYP1A2 inhibitors such as fluvoxamine can markedly raise levels; strong CYP3A inducers such as rifampin can reduce benefit.
Nighttime beta blockers may reduce effectiveness. Do not move or stop heart medicines yourself. Alcohol and other sedatives add impairment.
Everyday tips
Use a reliable nightly reminder and consistent sleep opportunity.
Bring sleep records to follow-up visits.
Your questions answered
Why does the dose time matter?
The goal involves the body’s daily clock. Irregular or extra doses can undermine the plan.
Should I expect an immediate sleeping-pill effect?
No. Sleep timing may take time to align even if you feel sleepy after a dose.
Storage and safety
Keep medication in its labeled container, away from excess heat and moisture and out of reach of children and pets. Do not share it. Ask a pharmacy about disposal of unused medication.
Sources
About this information
Educational handout; does not replace your prescription or provider's recommendations.
Educational inclusion does not mean this medication or its indications are treated at this practice. Review the guide for your exact product with your prescriber or pharmacist.