Most people's problem with antihistamines for sleep is they take too high a dose, assuming more is better. And when tolerance builds, taking more is not going to help because then you get more of the other stuff like anticholinergic effects.
Tolerance to sedation from antihistamines can build very rapidly.
I can't tell if the sedative properties of certain antihistamines results from their H1 antagonism or if it's because of their cross effect with antagonizing the adrenergic receptors.
Are all H1 antagonists innately sedating or is it just the first generation ones?
Just wondering if someone could supply some binding affinity charts to this thread. I think dopamine blockade increases melatonin production or something?
Here is info on the binding affinities (it would be nicer if they were bar graphs like the one I posted for diphenhydramine). I'm not psyched about the propensity for both antihistamine and antidopamine actions to cause/exacerbate RLS and other movement disorders though.
) Also shown affinity towards: (I'm not sure what the action on these is though? Diphenhydramine is a good and cheap option, but you gain a tolerance to it extremely fast, so everyday use is not really beneficial.
Even seroquel at tolerance-level dosing gave me very uncomfortable nightmarish RLS/insomnial hellacious torture that I would never wish to endure ever again.Mirtazapines sedation ime is not just H1 antagonism.Ive taken many of the drugs mentioned (havent tried the anti-psychs) and mirtazapine has a much more relaxing enjoyable sedation then say, hydroxyzine.Diphenhydramine has potent antagonization effects on Histamine H1 receptors, and Muscarinic acetylcholine receptors (all subtypes).Where as Quetiapine has potent antagonizing effects on Histamine H1, but also possesses antimuscarinic actions at M1 and M3.