1 What is Hetlioz?

Brand: Hetlioz

Generic: Tasimelteon

Hetlioz is used for the treatment of non-24-hour sleep-wake disorder (Non-24). It is a melatonin receptor agonist.

This medicine is available only through your doctor's prescription.

This product is available in the following dosage forms:

  • Capsule

2 What To Know Before Using

Before using Hetlioz, you must know all about the risks and complications associated with it. Your doctor will consider these risks before prescribing the drug and will inform you about them.

Following factors should be considered before taking this drug:


If you have had an allergic reaction to this drug in the past, inform your doctor. You should also tell your healthcare provider if you are allergic to any other drugs or food products.

Age-specific problems

The data regarding the effects of this medicine specific to the pediatric age group is not yet available. Its safety and efficacy have not been established in children.

The studies specific to the geriatric age group have not been carried out, therefore its safety and efficacy have not been established in older age group. However, geriatric population is more prone to having kidney, liver and heart problems.


Regarding the safety of usage of this drug during pregnancy, it comes under “C” category, which means that clinical trials on animals have revealed harmful effects to the developing fetus or relevant studies have not been performed.

Drug Interactions

Certain drugs should not be used together because they can interact inside the body which can have a harmful effect. On the other hand, certain drugs are allowed to be used together.

So, you should tell your doctor about any other medications you are taking. If there is a chance of interaction between those two drugs, the doctor may change the dose or may prescribe an alternative drug.

This medication should be used cautiously with the following drugs:

  • Abiraterone
  • Ciprofloxacin
  • Carbamazepine
  • Enoxacin
  • Fluvoxamine
  • Enzalutamide
  • Phenobarbital
  • Fosphenytoin
  • Phenytoin
  • Rifabutin
  • Primidone
  • Rifampin
  • St John's Wort
  • Rifapentine

Furthermore, certain medications should not be taken with alcohol or tobacco, which may also result in harmful interactions. Ask your doctor about the concurrent use of this drug along with alcohol or tobacco.

You should also inform your doctor about any other medical condition you may be suffering from.

3 Proper Usage

To use Hetlioz properly, you must follow all instructions given by your doctor. You should swallow this capsule as a whole. Don’t crush, break, or chew it. Take the dose of medicine at the same time every night, without food.

You should keep using this medicine for several weeks or months. It may take a while to work in some patients because of individual differences in the body clock (circadian rhythms).

This drug should be used exactly as prescribed by your doctor in order to avoid adverse effects. Do not overuse or misuse this drug and do not use it longer than the recommended time. Read all the instructions mentioned in the medication guide.

Missed dose

Do not miss any dose. The dose of this drug varies according to the condition of each person. The number of doses per day, the time interval between the doses and the length of time you have to take the medicine depends on your condition individually and all these factors should only be determined by your healthcare provider. Follow each and every instruction of your doctor and also read the label carefully.

In case you miss one dose of this drug, take it as soon as you can. If it is almost time for your subsequent dose, you can then skip the missed dose and continue with your regular dosing schedule. Do not take two doses at once.


This medicine should be stored at room temperature within a closed container, away from heat, direct light, and moisture. Keep this drug out of the reach of children. Do not store expired or outdated medicines or the medicine no longer needed.

4 Precautions To Take

Before using Hetlioz, there are some precautions you must take. This medication can cause drowsiness and sleepiness in some people. It can also cause a decrease in alertness and attention.

Your doctor will monitor the response to this medicine and look for any side effects. Therefore, regular follow-up is necessary during and after the treatment. Contact your doctor if your symptoms have not improved even after taking the full course of treatment. 

Avoid taking any other medicine unless thoroughly discussed with your doctor. Always ask your doctor before using any prescription, non-prescription or herbal medicine.

5 Potential Side Effects

As with many medications, there are several potential side effects associated with Hetlioz. Although these side effects may occur only in a handful of patients, but if they do occur, contact your physician immediately.

This medication is associated with the following side effects:

  • Chills or fever
  • Body aches or pain
  • Ear congestion
  • Cough
  • Headache
  • Nightmares
  • Nasal congestion, runny nose, or sneezing
  • Bladder, lower back, or side pain
  • Difficult, burning, frequent, or painful urination
  • Bloody or cloudy urine

Seek medical help instantly, if you experience any of these symptoms while on this drug. Also contact your healthcare professional immediately, if you have overdosed on this drug. If any of these side effects becomes more bothersome or does not go away, contact your doctor.