Who Should (And Should Not) Use Hetlioz?

Medication Treats Non-24 Sleep Disorder Among Blind People

A woman turns off her alarm clock. Getty Images

Perhaps you have heard the advertisements for a prescription medication to aid sleep called Hetlioz. You may wonder, “Should I use Hetlioz?” Learn who should use it, what possible reasons might exist to avoid it, and whether Hetlioz is an appropriate medication to treat your insomnia and excessive daytime sleepiness.

The Indications to Use Hetlioz

Hetlioz, sold under the generic name tasimelteon, is a prescription medication from Vanda that is used to treat a specific sleep disorder that occurs most commonly in totally blind people.

This condition, called Non-24-Hour Sleep-Wake Disorder (Non-24), is a circadian rhythm disorder in which cycles of insomnia and excessive daytime sleepiness occur over weeks. Non-24 occurs in about half of people who are totally blind without light perception.

Hetlioz works by affecting the receptors for melatonin within the brain, causing sleepiness and sleep to occur at a proper time.

Who Should Not Use Hetlioz?

Hetlioz is not approved for use by sighted people who do not experience Non-24.

Even among the totally blind with Non-24, there are situations that might require caution with use. Due to issues related to metabolism, these circumstances include people who: are elderly, have severe liver dysfunction, smoke cigarettes, or use alcohol or other medications that might depress the central nervous system.

Research suggests the drug may be harmful to a fetus in animal studies and human studies have not been performed.

The safety of use with breastfeeding is unknown.

Hetlioz use has not been studied in children but it may be prescribed for off-label use by a physician in appropriate situations.

What Other Options Exist to Treat Non-24?

If you are sighted and have difficulty with insomnia, you may seek treatment with other sleeping pills or even cognitive-behavioral therapy for insomnia (CBTI).

Excessive daytime sleepiness may suggest another sleep disorder, such as obstructive sleep apnea, and should be evaluated by a sleep specialist.

In blind people with Non-24, research has previously demonstrated that low doses of over-the-counter melatonin at the proper time and dose can effectively treat this condition without the use of a prescription medication.


"Hetlioz." Epocrates Rx Pro. Version 14.1, 2014. Epocrates, Inc. San Mateo, California.

Morgenthaler TI et al. “Practice parameters for the clinical evaluation and treatment of circadian rhythm sleep disorders: An American Academy of Sleep Medicine report.” Sleep. 2007; 30:1445-59.

Sack, RL et al. “Entrainment of free-running circadian rhythms by melatonin in blind people.” NEJM. 2000; 343(15)1070-1077.

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