What is the difference in terms of alcohol poisoning or overdose in terms of how it gets into the body? (Usually, it’s by drinking too much, but I’ve read that it’s now a dangerous fad to inhale alcohol vapors, because the vapor gets into the body far faster and isn’t broken down by the liver the way beer or whiskey is.) As for absorption, does most alcohol evaporate before it has time to get through the skin? (say, someone accidentally spills a bottle of pure isopropyl alcohol on their body)
Butt-chugging is dangerous
Puking is your greatest defence, I think, against drinking too much.
That wikipedia article on butt-chugging is not very good. Ethanol absorbed by the stomach and the small and large intestine leaves the gut and enters the portal vein, which drains through the liver before the blood gets back to the vena cava and the heart. This setup allows the liver to get the first crack at metabolizing the toxins and nutrients that your gut has absorbed. A fair percentage of the ethanol that you drink gets intercepted by the liver and broken down before it hits your brain. This is called first-pass metabolism. Eventually, the liver sees the ethanol in the blood again as it circulates back through, now via the hepatic artery, so it continues to clear ethanol from your blood over time.
The lower rectum, on the other hand, has venous drainage that empties directly into the internal iliac veins, which bypass the liver on the way to the heart. Thus the liver gets no first-pass opportunity to remove the ethanol before it hits the general circulation. Alcohol entering by this mechanism doesn’t ‘overwhelm’ the liver, it just bypasses it on its first trip around the body. It eventually does circle back around to the liver to be detoxified, at which point it’s no different than ethanol taken by mouth.
Ethanol vapor taken in through the lungs also avoids the first-pass metabolism by the liver, and causes a more rapid spike in blood alcohol levels. Alcohol-related experiments on rats, for example, often use ethanol vapor as a delivery method. Topical application of alcohol seems to cause little systemic absorption, but evaporation of that alcohol does produce vapor which can be inhaled and result in (low) detectable blood alcohol levels. See: Inhalation of Alcohol Vapor: Measurement and Implications.
Remembering that it’s not particularly difficult to drink a lethal amount of ethanol by mouth, I would say that it would take a smaller amount of ethanol taken per rectum or by inhalation to be lethal because of the lack of first pass breakdown. HOWEVER that assumes the total amounts absorbed are the same. A person who drinks a fifth of scotch and passes out, or a person who puts a fifth of scotch in their rectum and passes out, will both continue to absorb alcohol for as long as it is physically in their body, and their BAL could continue to rise for some time until they die. A person using an inhaler will, I suspect, have difficulty inhaling a lethal dose of ethanol without drowning or being attached to the machine somehow such that it continues to push ethanol into their lungs after they pass out. Or if they are in an enclosed space in a distillery tank or some such. Otherwise once the mask falls off your face the ethanol levels in the blood will start to fall.