Tasimelteon
Tasimelteon is a melatonin receptor agonist indicated for Non-24-Hour Sleep-Wake Disorder in totally blind individuals. It is a selective agonist at melatonin MT1 and MT2 receptors that helps synchronize the circadian rhythm in patients who lack light perception and therefore cannot naturally entrain their sleep-wake cycle to a 24-hour schedule.
Clinical Overview
Primary Clinical Applications
Tasimelteon is specifically indicated for Non-24-Hour Sleep-Wake Disorder (Non-24) in totally blind individuals. This rare condition affects people who are completely blind and cannot perceive light, causing their internal circadian clock to “free-run” on a cycle longer than 24 hours, leading to chronic sleep-wake disruption.
Mechanism and Clinical Benefits
Tasimelteon acts as an agonist at melatonin MT1 and MT2 receptors in the suprachiasmatic nucleus, the brain’s master circadian clock. By providing a consistent daily melatonin signal, it helps entrain the circadian rhythm to a 24-hour cycle in patients who lack the light cues that normally synchronize the biological clock.
Clinical Considerations
Tasimelteon must be taken at the same time every night to maintain circadian entrainment. It may take weeks to months to achieve full therapeutic benefit as the circadian system gradually synchronizes. The medication is specifically designed for totally blind patients and has not been studied in sighted individuals or those with partial vision.
Key Clinical Points
For totally blind patients with Non-24 only
Indicated specifically for Non-24-Hour Sleep-Wake Disorder in people without light perception. It has not been studied in sighted individuals or those with partial vision.
Benefit takes weeks to months
The circadian system entrains gradually, so early absence of effect is expected rather than treatment failure. Patients need to be told this or they will stop.
Same time every night is essential
Entrainment depends on a consistent daily signal. Variable timing defeats the mechanism entirely, which is a stricter requirement than for conventional hypnotics.
Take on an empty stomach
At least two hours after eating. Food substantially reduces absorption and therefore the strength of the circadian signal.
Fluvoxamine and smoking both interfere
Strong CYP1A2 inhibition by fluvoxamine should be avoided, while smoking induces CYP1A2 and lowers levels. Rifampin markedly reduces effectiveness.
Prescribing Information
Dosing & Administration
Non-24-Hour Sleep-Wake Disorder – Adults:
- Dose: 20 mg once daily
- Timing: Same time every night before bedtime
- Duration: Long-term therapy typically required
Administration:
- Take without food (at least 2 hours after eating)
- Same time every night to maintain circadian entrainment
- Swallow capsules whole
- Continue therapy even if benefits not immediately apparent
Indications
- Treatment of Non-24-Hour Sleep-Wake Disorder in totally blind individuals
Contraindications
- Known hypersensitivity to tasimelteon or any component
Warnings & Precautions
- Somnolence: May cause drowsiness; avoid driving until effects known
- Sleep-related activities: Complex behaviors while not fully awake reported rarely
- Timing critical: Must be taken at same time nightly for efficacy
- Delayed onset: May take weeks to months for full benefit
- Food effects: Take on empty stomach for optimal absorption
Drug Interactions
- Strong CYP1A2 inhibitors: Avoid concurrent use (fluvoxamine)
- Strong CYP3A4 inducers: May reduce tasimelteon effectiveness
- Rifampin: Significantly reduces tasimelteon levels
- Smoking: May reduce tasimelteon levels due to CYP1A2 induction
Adverse Reactions
Common (≥5%):
- Headache, increased alanine aminotransferase
- Nightmares, upper respiratory tract infection
Less Common:
- Somnolence, fatigue, nausea, abnormal dreams
Special Populations
- Hepatic Impairment: Severe impairment: not recommended
- Renal Impairment: No dose adjustment needed
- Pregnancy: Category C – use only if benefits outweigh risks
- Totally blind patients only: Not studied in sighted individuals
- Timing consistency: Critical for maintaining circadian entrainment
Frequently Asked Questions
What is Tasimelteon used for?
Tasimelteon is a melatonin receptor agonist indicated for Non-24-Hour Sleep-Wake Disorder in totally blind individuals. It is a selective agonist at melatonin MT1 and MT2 receptors that helps synchronize the circadian rhythm in patients who lack light perception and therefore cannot naturally entrain their sleep-wake cycle to a 24-hour schedule.
What class of drug is Tasimelteon?
Tasimelteon is classified as: Melatonin Receptor Agonist.
For totally blind patients with Non-24 only?
Indicated specifically for Non-24-Hour Sleep-Wake Disorder in people without light perception. It has not been studied in sighted individuals or those with partial vision.
Benefit takes weeks to months?
The circadian system entrains gradually, so early absence of effect is expected rather than treatment failure. Patients need to be told this or they will stop.
Same time every night is essential?
Entrainment depends on a consistent daily signal. Variable timing defeats the mechanism entirely, which is a stricter requirement than for conventional hypnotics.
Take on an empty stomach?
At least two hours after eating. Food substantially reduces absorption and therefore the strength of the circadian signal.
Source: FDA prescribing information (DailyMed)