Doxepin
In 2016 the American College of Physicians advised that insomnia be treated first by treating comorbid conditions, then with cognitive behavioral therapy and behavioral changes, and then with drugs; doxepin was among those recommended for short-term help maintaining sleep, on the basis of weak evidence. The 2017 American Academy of Sleep Medicine recommendations focused on treatment with drugs were similar. A 2015 AHRQ review of treatments for insomnia had similar findings.
Idiopathic hypersomnia
"Based on the role of histamine in keeping people awake (and hence the common side effect of anti-histamines such as diphenhydramine causing sleepiness), medications that act on histamine are under development for the treatment of excessive sleepiness." It remains to be seen whether these H3 antagonists (i.e., compounds such as pitolisant that promote the release of the wake-promoting amine histamine) will be particularly useful as wake-promoting agents in the treatment of idiopathic hypersomnia.