Antihistamine Receptor Affinity Charts and Sleep.


I've been playing around with different antihistamines at night to help improve sleep. I wake up every night at 2AM and toss and turn for two hours before finally falling back to sleep. It's very irritating.

So I found these affinity charts for several medications used as antihistamines and I thought they were really interesting. I'd never really seen anything like them before.

Here is the one for Benadryl (diphenhydramine):


You can see that while Benadryl does have significant H1 blockade, at higher doses it also has a wealth of effects on other receptors. It looks like this "H1>M1 (muscarinic Ach)>NET (Norepinephrine Transporter)>a1 (alpha 1)>5HTT (serotonin)". So when you take a higher dose of Benadryl for "better" sleep, you are actually increasing the stimulatory effect as well by hitting these other receptors.

So what is best for sleep? Well, obviously whatever works for you personally is best but according to these charts, two of the best are low dose Remeron and Doxypin because at low doses they are almost 100% pure histamine blocking only.

Here's Doxypin and Remeron::


Compare with something like Trazodone or Elavil:


Trazodone probably works better at around 50 mg because you get serotonin receptor blockade at lower doses first.

And Elavil is not a good choice at all, really.

This all comes from this blog post where you can read more if what I've written makes no sense. ;)

But the most important take away is that increasing a dose of a drug doesn't necessarily get you more sedation. It may actually get you less if you start activating wakeful type receptors at the higher doses.

Who Me?

Well-Known Member
Very interesting. I use antihistamine to sleep. Benadryl was my go to but now it causes tachycardia.

I use doxylamine and chlortrimeton too

But the ones here are not traditional antihistamines so interesting.

@Strike me lucky interestkng. @Upgrayedd note the comment on Elavil.

Who Me?

Well-Known Member
I've been taking 2 mgs atarax for a few days. It's less and less sedating. I'm still waking at 4 a.m. no matter what I take but I know it's helping with some crazy histamine issues.

I also know with trazodone the generic makes a huge difference.

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