# How fast is aspirin, etc supposed to take effect? **URL:** \ **Category:** Factual Questions\ **Created:** [March 29, 2007, 1:52pm UTC](https://boards.straightdope.com/t/how-fast-is-aspirin-etc-supposed-to-take-effect/397968 "2007-03-29T13:52:51Z")\ **Posts on this page:** 12\ **Page:** 1
**Author:** ![SmackFu](https://avatars.discourse-cdn.com/v4/letter/s/53a042/32.png) [@SmackFu](https://boards.straightdope.com/u/SmackFu)\ **Post date:** [March 29, 2007, 1:52pm UTC](https://boards.straightdope.com/t/how-fast-is-aspirin-etc-supposed-to-take-effect/397968/1 "2007-03-29T13:52:51Z")
Like how long after you ingest it is the drug dispersed? ---
**Author:** ![brewha](https://avatars.discourse-cdn.com/v4/letter/b/91b2a8/32.png) [@brewha](https://boards.straightdope.com/u/brewha)\ **Post date:** [March 29, 2007, 2:13pm UTC](https://boards.straightdope.com/t/how-fast-is-aspirin-etc-supposed-to-take-effect/397968/2 "2007-03-29T14:13:41Z")
20 min Cite? My SIL who is a pharmacist. YMMV ---
**Author:** ![Duck\_Duck\_Goose](https://avatars.discourse-cdn.com/v4/letter/d/50afbb/32.png) [@Duck\_Duck\_Goose](https://boards.straightdope.com/u/Duck_Duck_Goose)\ **Post date:** [March 29, 2007, 2:16pm UTC](https://boards.straightdope.com/t/how-fast-is-aspirin-etc-supposed-to-take-effect/397968/3 "2007-03-29T14:16:01Z")
When I take two aspirin on a full stomach for knee pain, I feel a sense of relief 20 minutes later, by the clock. YMMV. My understanding has always been (can’t find a cite, sorry) that in general it takes 20 to 30 minutes for any medication that’s swallowed to reach the bloodstream. Why do you want to know? ---
**Author:** ![vetbridge](https://avatars.discourse-cdn.com/v4/letter/v/b5e925/32.png) [@vetbridge](https://boards.straightdope.com/u/vetbridge)\ **Post date:** [March 29, 2007, 2:30pm UTC](https://boards.straightdope.com/t/how-fast-is-aspirin-etc-supposed-to-take-effect/397968/4 "2007-03-29T14:30:06Z")
While **brewha** is close enough for most purposes, I might add that pharmacokinetics can vary widely with the patients specifics (age, weight, blood pressure, last meal, etc). > **[Pharmacokinetics](https://en.wikipedia.org/wiki/Pharmacokinetics)** > > Pharmacokinetics (from Ancient Greek pharmakon "drug" and kinetikos "moving, putting in motion"; see chemical kinetics), sometimes abbreviated as PK, is a branch of pharmacology dedicated to describing how the body affects a specific substance after administration. The substances of interest include any chemical xenobiotic such as pharmaceutical drugs, pesticides, food additives, cosmetics, etc. It attempts to analyze chemical metabolism and to discover the fate of a chemical from the moment Ph... ---
**Author:** ![SmackFu](https://avatars.discourse-cdn.com/v4/letter/s/53a042/32.png) [@SmackFu](https://boards.straightdope.com/u/SmackFu)\ **Post date:** [March 29, 2007, 2:58pm UTC](https://boards.straightdope.com/t/how-fast-is-aspirin-etc-supposed-to-take-effect/397968/5 "2007-03-29T14:58:30Z")
[QUOTE=Duck Duck Goose] Why do you want to know? [/QUOTE] Just curious. I’m remarkably bad at checking this kind of thing. I take the pill and then once the pain goes away, I forget I took it. ---
**Author:** ![Cat\_Whisperer](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cat_whisperer/32/4839_2.png) [@Cat\_Whisperer](https://boards.straightdope.com/u/Cat_Whisperer)\ **Post date:** [March 29, 2007, 5:58pm UTC](https://boards.straightdope.com/t/how-fast-is-aspirin-etc-supposed-to-take-effect/397968/6 "2007-03-29T17:58:37Z")
My recent experience with severe shoulder pain and Tylenol is…twenty minutes. Let me add that 8 hr, extended release Tylenol for arthritis is amazingly effective for an over-the-counter drug (name brand and generic, both). ---
**Author:** ![ZipperJJ](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/zipperjj/32/211_2.png) [@ZipperJJ](https://boards.straightdope.com/u/ZipperJJ)\ **Post date:** [March 29, 2007, 6:31pm UTC](https://boards.straightdope.com/t/how-fast-is-aspirin-etc-supposed-to-take-effect/397968/7 "2007-03-29T18:31:16Z")
To hijack a bit - what about “heavier” drugs like Vicodin? I always see on TV (especially _House)_ the character is all in pain, lunges for his bottle, pops a pill (without water) and is instantly perky. Is that really how they work? ---
**Author:** ![ouryL](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ouryl/32/6067_2.png) [@ouryL](https://boards.straightdope.com/u/ouryL)\ **Post date:** [March 30, 2007, 2:20am UTC](https://boards.straightdope.com/t/how-fast-is-aspirin-etc-supposed-to-take-effect/397968/8 "2007-03-30T02:20:38Z")
_Half lives_ 300–650 MG dose: 3.1–3.2hrs 1 G dose: 5 hours 2 G dose: 9 hours ---
**Author:** ![GingerOfTheNorth](https://avatars.discourse-cdn.com/v4/letter/g/cdc98d/32.png) [@GingerOfTheNorth](https://boards.straightdope.com/u/GingerOfTheNorth)\ **Post date:** [March 30, 2007, 3:43am UTC](https://boards.straightdope.com/t/how-fast-is-aspirin-etc-supposed-to-take-effect/397968/9 "2007-03-30T03:43:27Z")
[QUOTE=ZipperJJ] To hijack a bit - what about “heavier” drugs like Vicodin? I always see on TV (especially _House)_ the character is all in pain, lunges for his bottle, pops a pill (without water) and is instantly perky. Is that really how they work? [/QUOTE] I suspect that might be due to a sense of relief, that they know what is coming. My experience is also twenty minutes. ---
**Author:** ![Lynn\_Bodoni](https://avatars.discourse-cdn.com/v4/letter/l/e47c2d/32.png) [@Lynn\_Bodoni](https://boards.straightdope.com/u/Lynn_Bodoni)\ **Post date:** [March 30, 2007, 3:45am UTC](https://boards.straightdope.com/t/how-fast-is-aspirin-etc-supposed-to-take-effect/397968/10 "2007-03-30T03:45:38Z")
[QUOTE=ZipperJJ] To hijack a bit - what about “heavier” drugs like Vicodin? I always see on TV (especially _House)_ the character is all in pain, lunges for his bottle, pops a pill (without water) and is instantly perky. Is that really how they work? [/QUOTE] I don’t know about Vicodin (it doesn’t work on me), but I get relief from Darvocet within half an hour or so. IV drugs will, of course, work even faster. ---
**Author:** ![panache45](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/panache45/32/64_2.png) [@panache45](https://boards.straightdope.com/u/panache45)\ **Post date:** [March 30, 2007, 4:46am UTC](https://boards.straightdope.com/t/how-fast-is-aspirin-etc-supposed-to-take-effect/397968/11 "2007-03-30T04:46:32Z")
With me, most pain killers take 45-50 minutes, and decongestants take about 70-75 minutes. ---
**Author:** ![GilaB](https://avatars.discourse-cdn.com/v4/letter/g/8e7dd6/32.png) [@GilaB](https://boards.straightdope.com/u/GilaB)\ **Post date:** [March 30, 2007, 5:27am UTC](https://boards.straightdope.com/t/how-fast-is-aspirin-etc-supposed-to-take-effect/397968/12 "2007-03-30T05:27:53Z")
It depends on lots of stuff, but one thing that varies from person to person is stomach emptying time. Some people’s stomachs empty out in 20 minutes, and some take up to two hours, which greatly affects how quickly things cross over into the bloodstream. Obviously a full/empty stomach matters, too, as does even whether you’re lying down or not! Apparently, Fundamentals of Toxicology _is_ occasionally relevant.