Spit, don't swallow - oral caffeine absorption

February 28, 2008 12:09 AM

I need some information on the amount of caffeine that can reasonably be absorbed through oral membranes.

I have a friend who's having some GI problems, but doesn't want to give up her daily kick of caffeine. She's planning on trying to brew up some strong coffee, then swish it in her mouth for a while, until some of the caffeine is absorbed (thus bypassing the GI tract all together)

This seems plausible, as we both know that many drugs can be absorbed through the lining of the mouth. (through the surface of the cheeks and tongue, one relevant term is "sublingual"). We disagree on how effective this method can be, though. I don't think the absorption rate will be high enough to make it worthwhile - she's convinced it will work.

Seems like a simple enough question, but I'm having trouble finding information on the rates of absorption. There's lots of literature on other drugs, and even a patent for a breath-spray type caffeine delivery system, but no solid information on how much she could expect to reach her bloodstream.

So, masters of Google-fu, can anyone find me a source that tells us whether this is feasible? Would it be more feasible with a higher concentration of caffeine, that came from, say a caffeine pill (crushed or otherwise)?

posted by chrisamiller to science & nature (16 comments total)

Your friend needs a caffine patch.
posted by bigmusic at 12:29 AM on February 28, 2008

Think Geek has a veritable plethora of caffeine-laden products that might not aggravate GI problems, like lip balm and soap.
posted by Addlepated at 12:56 AM on February 28, 2008

While I admit I fell for the joke the first time around, I have always wondered...

A little DMSO, a little caffeine, a nice big bandage to keep it on the skin...

Maybe a tube of Breath spray if I got that garlic taste in my mouth from the DMSO...

Hmmm...
posted by petethered at 1:58 AM on February 28, 2008

If she thinks it'll work, just smile and nod. It's not like going without caffeine is going to hurt her (much), and placebo is a wonderful thing. (My Googling says it takes 45 minutes for the stuff to be completely absorbed after swallowing, so I seriously doubt holding it in the mouth for 30 seconds is going to do much).
posted by Leon at 2:00 AM on February 28, 2008

Leon: I suspect you're right that it won't be all that effective (it may have some effect, but probably not as much as a cup of coffee). However, sublingual administration of some substances can be very effective, and much quicker than GI ingestion - substances can be absorbed directly into the bloodstream through the mucous membranes in the mouth. This also means that there's greater bioavailability, since less is lost to the digestive system.
posted by spaceman_spiff at 2:20 AM on February 28, 2008

This looks like a job for Caffeinated Nasal Spray!
posted by dansdata at 2:22 AM on February 28, 2008

Ok, different approach - Sublingual on Wikipedia. From reading that, maybe a couple of powdered caffeine tablets held under the tongue would be the most effective way to go? I still think coffee is going to be too dilute.
posted by Leon at 2:46 AM on February 28, 2008

I'm not sure how to put this, so I'll just say... suggested Google search term: "Coffee enema."
posted by hjo3 at 3:34 AM on February 28, 2008 [1 favorite]

I would be a little bit concerned about swishing strong coffee around for a while regularly - that can't be good for her teeth.
posted by dreamyshade at 4:19 AM on February 28, 2008

You don't say what your friend's GI problem is specifically, but she should know that caffeine itself, regardless of the method of administration, lowers the pressure of the lower esophageal sphincter and contributes to reflux.
posted by LittleMissCranky at 4:44 AM on February 28, 2008

There are caffeinated mints, nonetheless you'd be taking in a lot of sugar and other extraneous ingredients along with each dose. If she has GI problems, I would recommend advising her to look into cold brew methods. They are lower acid and a lot easier on your digestive system.

Oral absorption is completely adequate for many substances, it just depends on the dose. Chewing tobacco is a prime example, although you keep it more tucked against your gum and less swishing it around your mouth. Like you referenced, crossing the barrier of adequate transmission is a problem of concentration and time. Cold brew would also help here, as you end up with 1 lb of coffee in well under 1 gal of water, rather than in 4 gal through 10 pots of high acid coffee. But again, I still don't think you'd reach adequate concentration levels to simply unload a few ml into your gums and pick up a noticeable effect. If you could reduce the mixture down to a level where it would be effective it would probably be trivially easy to OD and/or difficult to dose accurately, to wit: "An acute overdose of caffeine, usually in excess of 250 milligrams – about three 8 fluid ounce cups of brewed coffee"

This thread may be of slight interest, there are better illustrations of the cold brew concentration mainlining, anyway.
posted by prostyle at 6:46 AM on February 28, 2008

What about good old No Doz & Vivarin? It's quite cheap, and for me at least, very easy on the stomach. Get it at any drugstore or supermarket...
posted by allen8219 at 9:07 AM on February 28, 2008

When I was a kid we dipped tea.
Whether we got spun off of that or off of being kids, we shall never know.
Seemed to work though.

However, it helps if you live in an area where dipping is considered cool.
Like a locker room.
posted by Seamus at 9:33 AM on February 28, 2008

I would second the caffeine soap available at ThinkGeek. It can seriously get you wired and leaves you minty fresh! By the way, I've been told (or read somewhere) that unlike the claims of the ad in ThinkGeek, you dont absorb the caffeine through your skin (something about the molecules being too big or whatever, Im no chemist), it all comes through inhalation of the steam, so a long shower is required. From personal experience, however, using this as a regular fix is probably not cost effective. The soap doesnt last very long.
posted by elendil71 at 9:53 AM on February 28, 2008

While I applaud mad science and all its applications, your addict friend might be better served by switching to a less caustic caffeine delivery system. How about a mate tea?

On the downside, she won't get to use the word "cuspidor" on a regular basis.
posted by chairface at 10:32 AM on February 28, 2008

Well, apparently the info I seek isn't easy to find, but maybe we'll do an experiment with a caffeine pills under the tounge and see what happens. (Nothing too crazy, where there's any risk of OD). Thanks for the suggestions, all.
posted by chrisamiller at 4:11 PM on February 28, 2008