It also kills off the good bacteria in your mouth, and if ingested the bacteria in your digestive system, which is why the formulation designed for ingestion is subject to prescription.
The floor cleaner version is similar to the ingested version but it is not the same thing and the differences matter.
> and if ingested ... which is why the formulation designed for ingestion
There are all sorts of things sold OTC for putting in your mouth or other mucus membranes, that would harm you if you swallowed the active dose. Eye drops, for example. Governments generally trust people to just... not do that. They require that the manufacturer put instructions to not ingest the thing on the label, and that's usually the end of it.
Also, there is a reason that mouthwashes have child-proof caps! They are, in fact, dangerous in general if you don't know what you're doing with them!
But chlorhexidine is no more dangerous than your average mouthwash. And far less dangerous than other things you can get ahold of without a prescription.
(And, given the implication of gingivitis gingipains in Alzheimer's, it might turn out to be a lot more dangerous to not sterilize your gums. Especially if you're old, immunoincompetent, and/or have lost many of your teeth, exposing more of the gum surface to regular microabrasion. Enabling OTC access to chlorhexidine mouthwashes could very well be highly-positive in global QALYs.)
> The floor cleaner version is similar to the ingested version but it is not the same thing
Yes, my point wasn't that you should put floor cleaner in your mouth; my point was that someone can buy things that contain a large amount of chlorhexidine gluconate OTC very easily — sometimes even pure! — and anyone who cares could then just distill the active ingredient out to ensure purity. It's not like these are intentionally denatured; none of the other ingredients have the same molecular weight.
Many (all?) in Canada have reformulated as alcohol-free. Unsure if it’s because water is cheaper than alcohol or to avoid a tobacco-style lawsuit because alcohol is linked to oral cancers.
Maybe because people drink the stuff, but I don’t think the manufacturers really had a problem with that.
Also it's OTC in europe
"It is well known that CHG causes considerable side effects, such as extrinsic staining, an alteration in taste perception, and an increase in calculus formation. The calculus surface itself may not induce inflammation in the adjacent periodontal tissue. However, calculus formation is known to be a factor in plaque retention as well as a reservoir for toxic bacterial products and antigens. In addition, a recent investigation has reported that treatment of Porphyromonas gingivalis biofilms with CHG for 5 min did not degrade their external structure or reduce the volume of protein and carbohydrate constituents. The residual structure following CHG exposure may accelerate calculus formation and may serve as an ideal substrate to promote new microbial adhesion."
https://bmcoralhealth.biomedcentral.com/articles/10.1186/s12...
But re: this part —
> In addition, a recent investigation has reported that treatment of Porphyromonas gingivalis biofilms with CHG for 5 min did not degrade their external structure or reduce the volume of protein and carbohydrate constituents.
IIRC this isn’t a surprising finding; CHG is supposed to do its work in combination with brushing and flossing, not on its own.
Picture a biofilm like a tree. A tree is a lot more brittle when it’s dead and dried out, than when it’s living and actively keeping itself hydrated.
You wouldn’t try to uproot a live tree; that’d be hell, since all the roots would be stretchy. It’d be like trying to snap a live green branch off a tree, times a thousand. Instead, you cut the tree down; let the stump decay and dry; and then pull it out.
Same with biofilms: live colonies are elastic and emit protective mucilage around themselves, rendering them resistant to physical onslaught from brushing. Kill them, though, and they become brittle and able to be abraded away.
But, of course, just as with antibiotics, an intervention that kills 99% of a biofilm colony won’t do much if you just do it once and then immediately stop, because that last 1% can use the dead bacteria and the biofilm itself as a growth medium to come right back. With antibiotics, you need to keep the bacteriostatic effect going for long enough for your immune system to pick off the stragglers. With oral rinses, you need the effect to last long enough for the combination of brushing/flossing, saliva, rubbing from the tongue, and abrasion of fibrous food, to fully clean the biofilm away.
You can buy chlorhexidine gluconate concentrate (which is still not all that "concentrated" — something like 2% w/v) in the form of a medical or veterinary scrub — or even a floor cleaner — over the counter. But dilute it to 0.15% (at which concentration it would now become not-painful to put it in your mouth; but also would cause it to expire after a couple of days) — and then add the stabilizers and preservatives to it necessary to have it last a few months at STP? Well, now it's a prescription product.
As far as I'm aware, there are no risks from "chronic" use of Peridex as one's every-day mouthwash. Chlorhexidine does the same thing the alcohol in regular mouthwash does — it kills bacteria in your mouth. The only difference is that chlorhexidine sticks around keeping your mucus membranes aseptic for around eight hours (if you don't eat anything), compared to an alcoholic mouthwash's couple-of-minutes. So it actually protects you on a long-enough timescale for your body to get in there and clear out any biofilms causing you gingivitis, canker sores, enamel erosion, etc. — rather than just treading water in the fight against those.
I almost wonder whether the mouthwash companies are in some sort of mutually-assured destruction arrangement, where they all would like chlorhexidine mouthwash to be something they could sell OTC, but they don't want their competitor to be the first to sell it OTC (and win the market by advertising increased effectiveness), and they're willing to lobby to keep it prescription-only so that that doesn't happen.