I am a regular volunteer with St. John Ambulance. It intrigues me that the standard protocol for a casualty experiencing chest pains is to chew a 300mg aspirin tablet, the argument being that chewing rather than swallowing the tablet results in the aspirin entering the blood stream faster.

From a biological standpoint, why is this the case? Given that the stomach and GI tract are specialised tissues to allow for maximum diffusion, why would it be faster to pass aspirin across the gums (bucaal administration?) tongue and cheeks which are not specialised for this purpose?

It is not just a special case for aspirin either, as Hypostop^TM/Glucogel^TM (acute treatment for hypoglycaemic shock, essentially concentrated sugar) is applied directly to the gums or cheek with a similar argument that in critical situations it is faster.

The only suggestion I could find was very vague from the "Merck Manual":

The stomach has a relatively large epithelial surface, but its thick mucous layer and short transit time limit absorption Which I assume could mean that it is the reduced absorption rate in the stomach that makes the oral membranes faster, yet it also says that the delay in the stomach is brief.

I'd be really interested to know the biology behind this!

The standard protocol for a person experiencing chest pains is to chew a 300mg aspirin tablet, the argument being that chewing rather than swallowing the tablet results in the aspirin entering the blood stream faster.

From a biological standpoint, why is this the case? Given that the stomach and GI tract are specialised tissues to allow for maximum diffusion, why would it be faster to pass aspirin across the gums (bucaal administration?) tongue and cheeks which are not specialised for this purpose?

It is not just a special case for aspirin either, as Hypostop^TM/Glucogel^TM (acute treatment for hypoglycaemic shock, essentially concentrated sugar) is applied directly to the gums or cheek with a similar argument that in critical situations it is faster.

The only suggestion I could find was very vague from the "Merck Manual":

The stomach has a relatively large epithelial surface, but its thick mucous layer and short transit time limit absorption Which I assume could mean that it is the reduced absorption rate in the stomach that makes the oral membranes faster, yet it also says that the delay in the stomach is brief.

I'd be really interested to know the biology behind this!