Famotidine Inhibits Carbonic Anhydrase (CA)

haidut

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It looks like both the H2 antagonists and the PPI drugs ara capable of inhibiting CA in vivo. This would explain some of the positive findings in studies testing PPI and H2 blockers in cancer and mental disease.
This study compared omeprazole, famotidine and ranitidine for inhibition of CA. Famotidine was the most potent, and a human equivalent dose of 0.6mg/kg was effective in vivo. Maximum effects of CA inhbition for all drugs was found after about 3 hours post ingestion. The human equivalent dose is well within the recommended therapeutic dosages for famotidine, which range from 10mg to 80mg daily for GI issues, and up to 300mg daily for mental disorders.

Effects of omeprazole, famotidine, and ranitidine on the enzyme activities of carbonic anhydrase from bovine stomach in vitro and rat erythrocytes ... - PubMed - NCBI

"...In this study, the effects of omeprazole, famotidine, and ranitidine on bovine stomach carbonic anhydrase (EC 4.2.1.1.) isoenzymes have been investigated in vitro. Bovine stomach carbonic anhydrase (CA) was purified from four different cell localisations of bovine stomach using affinity chromatography by Sepharose 4B-L-tyrosine sulphanilamide. The inhibition or activation effects of three different medical drugs on CA isoenzymes were determined using esterase activity and the CO(2)-hydratase method by plotting activity % vs. [medical drug]. The K(i) values for omeprazole, famotidine, and ranitidine were determined in all localization CA, respectively. The I(50) values of the drugs exhibiting an inhibition effect were found by means of these graphs. It was observed that omeprazole, famotidine, and ranitidine showed inhibition of bovine stomach CA activity. In addition, in vivo studies were performed for these medical drugs in Sprague-Dawley rats. It was demonstrated that CA in erythrocytes was significantly inhibited by these drugs to 3 h."

Edit: 11/26/2018
A more recent study found that the anti-ulcer effect of famotidine is likely due to its inhibition of CA, which affects H. pylori viability, and not because it inhibits acid production.
Famotidine, an Antiulcer Agent, Strongly Inhibits Helicobacter pylori and Human Carbonic Anhydrases. - PubMed - NCBI
 
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Philomath

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How does Famotidine compare to acetazolamide? If you one is trying to increase CO2, it seems like there are additional benefits to Famotidine
 
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haidut

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Philomath said:
post 103111 How does Famotidine compare to acetazolamide? If you one is trying to increase CO2, it seems like there are additional benefits to Famotidine

The dose of famotidine required to inhibit CA was in the range of 0.6mg/kg per day. The human schizophrenia study used 200mg daily, so the increase in CO2 may be a reason for the beneficial effects.
 
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sunmountain

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I've been wondering about the dosage. Presently I'm taking 10mg x 2 daily. At the above dosage, I would need to take nearly 40mg, or double.

How do people counter the risks of low acid at higher dosages? Invitation to bacteria? Also since hypo's are already low in acid (which is why we take carrot salad with vinegar), is it a good idea to take famotidine at higher doses?

In my case, I'm just coming off killing H. Pylori with prevpak, and it could be that my stomach has gotten used to producing too much acid, and it may take a while to normalize.
 

What-a-Riot

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@haidut in the original post you said .6mg/kg was effective in vivo but said in the next that the dose required to inhibit CA was in the hundreds of mg, can you give us some clarification on how famotidine can be used for this purpose?
 
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haidut

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@haidut in the original post you said .6mg/kg was effective in vivo but said in the next that the dose required to inhibit CA was in the hundreds of mg, can you give us some clarification on how famotidine can be used for this purpose?

The 0.6mg/kg dose was correct. The hundreds of milligrams reference is a typo as I was probably thinking of the dose used for various mental disorders and even autism.
 

DaveFoster

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@haidut

Do you think famotidine is akin to cyproheptadine in its safety profile and can be used indefinitely? Anything to look out for?

The protective effects of cyproheptadine only lack properties as a CA inhibitor; cypro and famotidine would cover all of Peat's recommendations for degenerative conditions (anti-cholinergic, anti estrogen, CA inhibitor, etc.)
 
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haidut

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@haidut

Do you think famotidine is akin to cyproheptadine in its safety profile and can be used indefinitely? Anything to look out for?

The protective effects of cyproheptadine only lack properties as a CA inhibitor; cypro and famotidine would cover all of Peat's recommendations for degenerative conditions (anti-cholinergic, anti estrogen, CA inhibitor, etc.)

I think there was a study showing prolonged use may lead to thrombocytopenia. Some people have reported bleeding issues with high doses (80mg) a day. Other than that, I think it's a pretty good OTC drug. But for carbonic anhydrase inhibition I think thiamine may be safer and probably more effective even though it does not have the other benefits of famotidine:
Thiamine Is A Carbonic Anhydrase Inhibitor As Effective As Acetazolamide
 

DaveFoster

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I think there was a study showing prolonged use may lead to thrombocytopenia. Some people have reported bleeding issues with high doses (80mg) a day. Other than that, I think it's a pretty good OTC drug. But for carbonic anhydrase inhibition I think thiamine may be safer and probably more effective even though it does not have the other benefits of famotidine:
Thiamine Is A Carbonic Anhydrase Inhibitor As Effective As Acetazolamide
Interesting; it looks like thrombocytopenia can be exacerbated by NSAIDs as well (no surprise).

Thrombocytopenia induced by both aspirin and clopidogrel in the same patient. - PubMed - NCBI

It would be interesting to know if the risk increases with co-administration of famotidine with aspirin, as this is what I'm doing at the moment, along with many 70+ year-olds.
 

charlie

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It would be interesting to know if the risk increases with co-administration of famotidine with aspirin, as this is what I'm doing at the moment, along with many 70+ year-olds.
Are you still taking both?

I am taking famotidine for GERD but just started taking aspirin and it is helping with the GERD requiring less famotidine, however I still need to take the famotidine. I noticed my gums were bleeding more, got some K2 on the way to counteract that.
 

DaveFoster

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Are you still taking both?

I am taking famotidine for GERD but just started taking aspirin and it is helping with the GERD requiring less famotidine, however I still need to take the famotidine. I noticed my gums were bleeding more, got some K2 on the way to counteract that.
I am; I take 20 mg famotidine with 300 mg aspirin. I'm going to bump up to 500 mg aspirin.

Famotidine is very well tolerated, selective, and safe.

Aspirin, as you know is probably the most protective drug in existence.

I think K2, glycine, aspirin, and famotidine is a killer combo, and it helps me quite a bit.

Ensuring a regular, quick transit might help with the minor increased risk of SIBO with famotidine.
 

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Texon

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I've been wondering about the dosage. Presently I'm taking 10mg x 2 daily. At the above dosage, I would need to take nearly 40mg, or double.

How do people counter the risks of low acid at higher dosages? Invitation to bacteria? Also since hypo's are already low in acid (which is why we take carrot salad with vinegar), is it a good idea to take famotidine at higher doses?

In my case, I'm just coming off killing H. Pylori with prevpak, and it could be that my stomach has gotten used to producing too much acid, and it may take a while to normalize.

@haidut @Peata I know this is an older thread but just found something that may be helpful. Famotidine appears to lower blood sugar.......
https://www.google.com/url?sa=t&sou...FjABegQICBAB&usg=AOvVaw3vTdxNSBIg2GTR7DoXi73P
Then, for those concerned about low stomach acid there is this....
Thiamine And Thyroid Fatigue - Dr. Izabella Wentz
 
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haidut

haidut

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@haidut @Peata I know this is an older thread but just found something that may be helpful. Famotidine appears to lower blood sugar.......
https://www.google.com/url?sa=t&sou...FjABegQICBAB&usg=AOvVaw3vTdxNSBIg2GTR7DoXi73P
Then, for those concerned about low stomach acid there is this....
Thiamine And Thyroid Fatigue - Dr. Izabella Wentz

We've mentioned this effect of famotidine on the forum in the past.
Famotidine Increases Glycogen, Improves Glucose Metabolism

It is likely due to its anti-serotonin effects. Anti-serotonin drugs lower blood glucose by improving metabolism and lowering cortisol.
Famotidine Is A Powerful Anti-serotonin Drug, Can Even Treat Serotonin Syndrome
 
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haidut

haidut

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Bump.
Just added a new study to the original post confirming the potent CA inhibition effects of famotidine and claiming that its anti-ulcer effects are likely due to CA inhibition and not so much reducing gastric acid levels.
 

Murtaza

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@haidut i know its a bit off topic but ive seen you suggest cypro for cushing's due to its anti-serotonin properties. Any chance famotidine can be used for cushing's too? And if yes what would be the dosage?
 

Spartan300

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Anyone know whether famotidine's CA effect could be used for high intra ocular pressure?
 

LCohen

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Spartan300

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@LCohen Thanks. I'm looking for alternatives to the prostaglandin/beta blocker drops I'm currently using which I think may be having a detrimental effect on my health/metabolism.
 

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