I started taking this for allergies in 2010, but I increased my use in late 2011. Around this time, I was coming off of Prilosec and trying to use acid reducers as necessary, but they caused me side effects.
I noticed, however, that chlorpheniramine seemed to be acting as an acid reducer for me.
Now chlorpheniramine was originally invented to block H1 and thus make allergy symptoms better. The acid reducers were designed to block H2 and reduce stomach acid. But they are both types of antihistamine.
This is one of those things that’s hard to google, as you get 2,000 articles all saying the same thing. But maybe your google-fu is better than mine, or maybe you just know. I wonder if chlorpheniramine acts as an H2 blocker as well, even though it was not originally intended as one. It’s a first-generation antihistamine and may not be very selective.
Well, CPA is an H1 blocker, and it’s felt that these receptors are not found in great abundance in the stomach, which is rich with H2 receptors, not H1 receptors.
However this article does show synergistic effect in ulcer healing by concomitant use of the H1 blocker CPA and the H2 blocker Famotidine. The authors therefore posit that H1 blockers do play some role in gastric secretion and also protection of gastric mucosa from erosions.
Certainly further research is needed. Can I have your stomach?
I would gladly have given it to you a few months ago. It has greatly healed since then, thank goodness. Over a year of pretty bad GERD and other symptoms.
Are you sure that CPA is NOT an H2 blocker too? I.e., it was intended as an H1 blocker but actually has some H2 action? I would guess not, as it would have been mentioned in the article you provided if it were.
My research, limited though it was, indicated that sometimes H2 blockers are used in treating diseases normally treated with H1 blockers, such as urticaria. Antihistamines are interesting drugs.
Ach. I had the same article to offer up. Their hypothesis is that H1 receptors provide synergistic help in healing acid damage by some other effects on mediators of inflammation. I am not sure however if they ruled out any cross reactivity and that is your question: is chlorpheniramine a pure H1 blocker, or does it have any cross over effect on H2s?
Certainly the converse is true: as you note, we do use H2s for additive H1 effect in treating persistent hives with regularity.
If nothing else that study though confirms your personal experience with an animal model: using chlorpheniramine with an H2 blocker gives better healing than using either alone, and likely would allow for a decrease in the H2 dose.
Cool. I could not use famotidine and had to quit. Believe it or not, it had a weird sexual side effect that caused something close to anorgasmia. I quit the famotadine and it resolved immediately. I had tried ranitidine in the past. It had a similar though not so drastic effect but made it hard to urinate. Those drugs are out for me, I guess.
So the effect of the CPM is now seen in isolation. It could be that I resolved my GERD and I’m overall just better. But it does seem to keep the acid down every time I take it. By the way, it also works as a superb antihistamine for me for allergies and does not make me drowsy at all.