Antihistamines could even work without any allergy since they are typically used as mild sleeping aids. They are also used often off-label for stress reduction. [0]
I find the steroids even more effective but they seem to exacerbate my anxiety after a few days though. Still haven't figured that out.
With regular use antihistamines quite quickly lose their drowsiness effects. But it's definitely a nice side effect for sleeping challenged folks. Azelastine is a second generation antihistamine so not particularly drowsiness inducing.
One of the interesting Azelastine quirks, is it's apparently somewhat antiviral [1].
> Theoretically, these drugs might increase the risk of dementia by blocking a particular brain neurotransmitter or increasing brain inflammation. In the past decade, several studies have suggested that these pills might increase the risk of dementia, while other studies have found no risk. And all the studies are inherently flawed.
Desloratadine is considered to have a low anticholinergic burden, and of course not crossing the BBB readily should reduce risks further.
But it is one of the more anticholinergic second gen antihistamines, make of that what you will, still miles behind something like Benadryl. Fexofenadine is apparently a less anticholinergic alternative.
[0] https://fherehab.com/learning/surprising-antihistamine-anxie...