The orexin-1 and orexin-2 receptors are two G protein-coupled receptors that 
bind the neuropeptides orexin-A and orexin-B. Dual antagonism of the receptors 
by small molecules is clinically efficacious in the treatment of insomnia, where 
the most advanced molecule suvorexant has recently been approved. The scope of 
this article is to review the small molecule orexin receptor antagonist patent 
literature between January 2012 and January 2014.