<prompt> Which orexin receptor antagonist is approved for treatment of insomnia ?SuvorexantDoxepinRitanserinAgomelatine  <response>: Suvorexant MOA : Orexin 1 and 2 receptors inhibitor Orexin antagonist enhance REM and non-REM sleep. Suvorexant decreases sleep onset latency Dose : 10-mg dose within 30 min of going to bed SE : Daytime somnolence 