diphenhydramine: fun, while you're still breathing

i was watching the tv show "house" tonight, about a vicodin-popping, misanthropic doctor played by hugh laurie. in this episode he has hay fever, and treats it by taking 1000 milligrams of benadryl at the beginning of the show and snorting benadryl further along in the show.

watching that, i thought the writers were idiots. didn't they know that over-the-counter benadryl is only 25 milligrams? taking 40 pills would suck, and i would imagine it's a lethal dose. it turns out that it is a lethal dose for some people, but people are willing to take a lot of pills for a high.

it appears that people regularly take more than 600 milligrams (more than 24 pills) of diphenhydramine (the active ingredient of benadryl) recreationally, with the side effects that sometimes take them to the hospital. it also appears that people are willing to take scores of pills to get high.

the scientific literature doesn't say much. if rats and humans are equally sensitive to diphenhydramine, then 50% of a group of 180 pound humans who took 41 grams (41,000 milligrams, or 820 pills) of diphenhydramine would die. if human sensitivity is more like mice, it would take 2,870 milligrams (58 pills) to have the same effect. erowid notes that "a lower dose will still kill a smaller proportion of the subjects."” there looks like there is some more definitive literature on humans here, but it requires working backward to dosage levels from blood plasma levels, which i didn't take the time to estimate.

the bottom line: i was wrong in thinking that the writers were far outside the realm of reality, but taking that much benadryl is risky.