Hetlioz (Tasimelteon)

Hetlioz is indicated for the treatment of circadian rhythm sleep disturbances, especially in individuals with non-24-hour sleep-wake disorder. It may be considered when lifestyle adjustments and non‑pharmacologic measures are insufficient.

• Management of non-24-hour sleep-wake disorder in blind or sighted patients.
• Adjunct therapy for irregular sleep patterns linked to circadian misalignment.
• Support for patients with delayed sleep phase disorder when other options fail.
• May improve daytime alertness and nighttime sleep quality in affected individuals.
• Used under physician supervision as part of a comprehensive sleep‑health plan.

• Tasimelteon selectively activates melatonin MT1 and MT2 receptors in the suprachiasmatic nucleus, the central regulator of the circadian clock. By mimicking endogenous melatonin, it helps synchronize the internal biological rhythm with the external light‑dark cycle, facilitating proper timing of sleep and wakefulness without directly inducing sedation.

Common side effects of Hetlioz are generally mild and may include:

Common

• Headache
• Nausea
• Fatigue or drowsiness
• Dizziness
• Upper respiratory tract infection
• Diarrhea

Serious

• Severe allergic reaction (anaphylaxis)
• Mood changes or depression
• Suicidal thoughts or behavior
• Significant liver enzyme elevation
• Vision disturbances

Before starting Hetlioz, patients should discuss their medical history with a healthcare professional.

• Not recommended for use during pregnancy or breastfeeding unless clearly needed.
• Caution in patients with hepatic impairment; liver function may need monitoring.
• May exacerbate depressive symptoms; monitor mood changes.
• Use with caution in individuals with a history of allergic reactions to melatonin or related compounds.
• Avoid abrupt discontinuation; tapering may be advised to prevent rebound insomnia.
• Ensure regular follow‑up to assess efficacy and safety.

Hetlioz can interact with other medications, affecting its efficacy or safety.

Avoid

• Strong CYP1A2 inhibitors (e.g., fluvoxamine) that may increase tasimelteon levels.
• Concurrent use with other melatonin receptor agonists.

Use with caution

• CYP1A2 inducers (e.g., smoking, rifampin) which may reduce effectiveness.
• Central nervous system depressants that could enhance drowsiness.
• Antidepressants, especially SSRIs, due to potential mood effects.
• Medications affecting hepatic metabolism, requiring liver function monitoring.
• Over‑the‑counter sleep aids, to avoid additive sleep‑related side effects.