Orexin Receptor Antagonist Examples
Suvorexant is the primary FDA-approved orexin receptor antagonist, with lemborexant and daridorexant representing newer dual orexin receptor antagonists (DORAs) also approved for insomnia treatment. 1, 2
FDA-Approved Dual Orexin Receptor Antagonists (DORAs)
The following orexin receptor antagonists are currently available for clinical use:
Suvorexant
- First-in-class DORA approved by the FDA
- FDA-approved doses: 15-20 mg for non-elderly adults, 15 mg for elderly patients 1
- Indicated for sleep maintenance insomnia
- Demonstrated moderate-strength evidence for improving sleep outcomes with 16-minute increase in total sleep time 1
Lemborexant
- Second-generation DORA approved for insomnia
- Currently being validated in primary insomnia populations 3
Daridorexant
- Newer DORA with distinctive pharmacokinetic profile 4
- Recently studied for delirium prevention after cardiac surgery 5
Selective Orexin Receptor Antagonists
Seltorexant
- Selective orexin-2 receptor (OX2R) antagonist
- Still in clinical development (has not reached Phase 3) 3
- Three published RCTs in major depressive disorder, with limited efficacy demonstrated 6
Other Selective Antagonists (Research/Development Stage)
- MK-1064: Selective OX2R antagonist, completed Phase I trials 7
- Nivasorexant: First orexin-1 selective receptor antagonist, explored for eating disorders 8
Investigational Compounds
Several DORAs have been studied but are not widely available:
- Filorexant: Investigated in depression trials with limited success 6
- Almorexant: Now primarily used as research tool in animal studies due to safety concerns 3
Clinical Context
The American Academy of Sleep Medicine suggests using suvorexant for sleep maintenance insomnia in adults (WEAK recommendation). 2 The FDA warns of cognitive and behavioral changes, complex behaviors (sleep driving), worsening depression, sleep paralysis, and hallucinations with orexin receptor antagonists 1.
The primary adverse effect is somnolence (7% vs 3% placebo), though serious adverse effects are rare at FDA-approved doses 1. These agents represent a mechanistically distinct class from traditional benzodiazepine and non-benzodiazepine hypnotics, potentially offering advantages for long-term treatment without dependence or tolerance 4.