WEBVTT - How Does Aspirin Know Where to Go in Your Body? 0:00:01.840 --> 0:00:07.600 Welcome to Brainstuff, a production of iHeartRadio. Hey brain Stuff, 0:00:07.640 --> 0:00:12.840 Lauren Bogelbaum. Here, we all experience some aches and pains 0:00:12.880 --> 0:00:15.200 as we move through the world in are weird and 0:00:15.240 --> 0:00:20.240 wonderful human bodies. Sometimes we take something to ease that pain, 0:00:20.800 --> 0:00:24.279 and on a global level, that something is most often 0:00:24.560 --> 0:00:30.120 aspirin or pacetylsalicylic acid. About forty thousand metric tons of 0:00:30.160 --> 0:00:34.199 aspirin is produced and consumed every year. That's over one 0:00:34.280 --> 0:00:39.760 hundred billion tablets. It's not only used for headaches. It 0:00:39.840 --> 0:00:43.440 can ease fevers and inflammation too, and millions of people 0:00:43.479 --> 0:00:47.440 take aspirin to help prevent heart attacks. There are good 0:00:47.479 --> 0:00:50.520 reasons a doctor might say, take to aspirin and call 0:00:50.560 --> 0:00:54.040 me in the morning. So today let's talk about how 0:00:54.080 --> 0:00:58.000 aspirin works and how it doesn't, and how some good 0:00:58.080 --> 0:01:01.960 science helped it become the most common drug in the world. 0:01:03.000 --> 0:01:07.400 As far back as three thousand BCE or thereabouts, ancient 0:01:07.440 --> 0:01:10.800 Mesopotamian physicians were writing about the use of parts of 0:01:10.800 --> 0:01:17.080 the willow tree to treat pain and inflammation. The ancient Chinese, Egyptians, Greeks, 0:01:17.080 --> 0:01:21.440 and Romans all recorded their use of willow extracts but 0:01:21.480 --> 0:01:25.240 it wasn't until the eighteen hundreds ce after the birth 0:01:25.240 --> 0:01:28.160 of the field of chemistry, that we started to understand 0:01:28.240 --> 0:01:32.520 why willow can work for these purposes. In the eighteen twenties, 0:01:32.680 --> 0:01:37.319 a few different chemical detectives, including Friedrich Buchner and Henri LaRue, 0:01:37.840 --> 0:01:40.959 isolated an extract of willow that was very bitter and 0:01:41.120 --> 0:01:44.280 very potent for use in treatment of things like rheumatism. 0:01:45.360 --> 0:01:49.640 They called it salasin, after a Latin word for willows salix. 0:01:50.880 --> 0:01:53.720 Over the next couple of decades, other chemists figured out 0:01:53.720 --> 0:01:56.960 the molecular structure of salacin and how it can be 0:01:57.040 --> 0:02:02.240 oxidized to produce the related compound salcilic acid, and then 0:02:02.360 --> 0:02:06.280 how to synthesize salasilic acid at a large scale in labs. 0:02:07.480 --> 0:02:10.640 In the eighteen seventies, due to this discovery, the Hayden 0:02:10.720 --> 0:02:15.080 Chemical Company in Germany became the first ever industrial manufacturer 0:02:15.240 --> 0:02:19.200 of any drug, and the commercial market for salasylic acid 0:02:19.280 --> 0:02:22.560 boomed for use in treating pain and swelling in diseases 0:02:22.600 --> 0:02:27.000 like arthritis and fever. In illnesses like the flu. The 0:02:27.120 --> 0:02:29.720 problem with salasilic acid is that it can upset the 0:02:29.800 --> 0:02:33.320 user's stomach fairly badly and even cause bleeding in the 0:02:33.360 --> 0:02:37.720 digestive tract at high doses, but researchers were working on 0:02:37.800 --> 0:02:42.160 it enter one of Hayden's national rivals, Bayer in Company. 0:02:43.360 --> 0:02:47.000 In the eighteen nineties. Chemists at Beayer reasoned that perhaps 0:02:47.040 --> 0:02:50.400 salicilic acid was so hard on the stomach because it's 0:02:50.440 --> 0:02:53.880 an acid. They knew from research back in the eighteen 0:02:53.919 --> 0:02:57.400 fifties in France that you can use chemical reactions to 0:02:57.919 --> 0:03:00.360 cover up one of the acidic parts of seala silic 0:03:00.400 --> 0:03:05.120 acid with an acetyl group, converting it to acetyl salicilic acid. 0:03:06.320 --> 0:03:10.320 They figured out how to synthesize pure medical grade aceetyl 0:03:10.320 --> 0:03:13.480 salicilic acid, and after a couple of years of testing, 0:03:13.800 --> 0:03:17.600 Beyar patented this effective and easier on the stomach medication 0:03:18.040 --> 0:03:22.720 under the trade name aspirin in eighteen ninety nine. They 0:03:22.760 --> 0:03:25.680 got the name by combining a for a setyl with 0:03:25.720 --> 0:03:29.200 a word derived from spyriea, which is the genus name 0:03:29.240 --> 0:03:31.960 for metal sweets, which are other plants that you can 0:03:32.000 --> 0:03:36.240 get salasin from. Today, the name aspirin has been role 0:03:36.360 --> 0:03:40.760 generic in a number of countries. There's actually a bit 0:03:40.800 --> 0:03:44.200 of a debate now about who at Bayer was responsible 0:03:44.240 --> 0:03:48.560 for synthesizing this compound. For decades, corporate lore said it 0:03:48.600 --> 0:03:51.119 was a junior chemist by the name of Felix Hoffmann, 0:03:51.440 --> 0:03:54.839 whose father had arthritis, so he was motivated to help 0:03:54.920 --> 0:03:59.080 ease his side effects from taking salicilic acid. But one 0:03:59.160 --> 0:04:02.040 hundred years after aspirn came out, at the turn of 0:04:02.040 --> 0:04:06.480 the twenty first century, credible evidence arose that Hoffmann's boss, 0:04:06.800 --> 0:04:12.640 one Arthur Eisngrun, was more responsible, but because Eisngrune was Jewish, 0:04:12.840 --> 0:04:15.840 his involvement was downplayed. With the rise of the Nazi regime, 0:04:16.800 --> 0:04:21.800 It's a mystery of history. Another long running mystery that 0:04:21.839 --> 0:04:25.080 has since been solved is how aspirin works in the body. 0:04:25.880 --> 0:04:29.200 We didn't know for sure until the nineteen seventies, when 0:04:29.240 --> 0:04:32.400 a team of pharmacologists and biochemists came up with proof, 0:04:32.960 --> 0:04:35.120 for which they were rewarded the Nobel Prize in Medicine 0:04:35.160 --> 0:04:38.760 in nineteen eighty two. It took humanity all of these 0:04:38.800 --> 0:04:43.320 millennia to figure it out, partially because pain is complicated 0:04:44.040 --> 0:04:47.320 like no one is totally sure how it works, and 0:04:47.360 --> 0:04:51.880 the more we learn, the more questions seem to arise. Okay, 0:04:52.520 --> 0:04:57.080 like all other sensory experiences. Pain exists only because your 0:04:57.120 --> 0:05:01.560 brain says it does, your body's way of telling you 0:05:01.640 --> 0:05:05.920 that something has gone wrong that needs your attention. Let's say, 0:05:05.960 --> 0:05:08.599 for example, that you hit your thumb with the hammer 0:05:08.880 --> 0:05:12.320 instead of the nail you're aiming for. Please don't try 0:05:12.320 --> 0:05:15.920 this at home. Now. Your thumb has nerve endings in it. 0:05:16.400 --> 0:05:19.720 These are little detectors in your joints and skin that 0:05:20.000 --> 0:05:24.719 feel things like heat, vibration, and everything from featherlight touch 0:05:25.080 --> 0:05:28.120 to the big crushing shock of being hit with the hammer. 0:05:29.040 --> 0:05:33.520 There are different receptors for each of these types of sensations. Also, 0:05:34.000 --> 0:05:37.200 when you hit your thumb and damage that tissue, nearby 0:05:37.320 --> 0:05:40.839 cells will release some chemicals that make your nerve endings 0:05:40.960 --> 0:05:45.400 register the crushing shock more strongly, like turning up the volume. 0:05:46.160 --> 0:05:52.159 Some of those chemicals are ones called prostaglandins. So very basically, 0:05:52.400 --> 0:05:55.240 you smash your thumb and the nerve endings involved send 0:05:55.520 --> 0:05:58.760 now strong signals up through your nervous system and into 0:05:58.760 --> 0:06:02.320 your brain, which which decides that these signals mean hey, 0:06:02.680 --> 0:06:07.560 that hurts. The pain you experience is useful information because 0:06:07.560 --> 0:06:10.200 it tells you that your thumb is damaged and that 0:06:10.279 --> 0:06:12.880 you should put the hammer down and be careful with 0:06:12.920 --> 0:06:17.719 the thumb until it's healed. Prostaglandins contribute only a portion 0:06:17.920 --> 0:06:21.239 of the total pain signal, but it's an important portion, 0:06:22.160 --> 0:06:25.719 and prostaglandins also help cause the site of the injury 0:06:25.760 --> 0:06:29.600 to swell up. This bathes the injured tissue in blood 0:06:29.720 --> 0:06:33.240 and helps rush immune system resources into protect it and 0:06:33.320 --> 0:06:38.560 start the healing process. Basically, it's a good system, but 0:06:38.760 --> 0:06:43.039 a few problems can arise. First Off, pain is not 0:06:43.160 --> 0:06:48.480 a neutral feeling. It's emotionally upsetting, so once you've registered 0:06:48.480 --> 0:06:52.800 your bodily damage, having that pain signal continue isn't fun 0:06:53.120 --> 0:06:58.960 or even particularly useful. Secondly, something's hurt without there being 0:06:59.000 --> 0:07:02.080 a hammer or or open flame, or some other source 0:07:02.080 --> 0:07:05.279 of damage that you can avoid. You might get a 0:07:05.320 --> 0:07:09.000 headache because your scalp and neck muscles are contracted from stress, 0:07:09.200 --> 0:07:13.320 or because a blood vessel in your brain has a spasm. Thirdly, 0:07:13.640 --> 0:07:17.360 as we've talked about before on the show, autoimmune conditions 0:07:17.560 --> 0:07:21.200 like arthritis or psoriasis can cause your immune system to 0:07:21.320 --> 0:07:26.400 turn on healthy tissue, causing too much inflammation, which itself 0:07:26.480 --> 0:07:30.880 can be painful and even damaging. These processes appear to 0:07:30.920 --> 0:07:36.000 involve prostaglandins as well. Aspirin helps with these problems by 0:07:36.200 --> 0:07:40.960 stopping your tissue from releasing prostaglandins by preventing your cells 0:07:41.000 --> 0:07:46.720 from making them. Okay, cells working in damaged tissues produce 0:07:46.800 --> 0:07:52.760 prostaglandins using an enzyme called cyclooxygenase two, or COX two. 0:07:53.000 --> 0:07:55.640 COX two can be found and lots of normal tissues, 0:07:55.840 --> 0:07:57.840 but much more of it is made in tissue that's 0:07:57.880 --> 0:08:01.920 been hurt in some way. Aspirin, as it turns out, 0:08:02.400 --> 0:08:05.520 sticks to COX two and won't let it do its job. 0:08:06.160 --> 0:08:09.240 It's like sticking gum in a lock instead of a key. 0:08:10.160 --> 0:08:12.720 Don't try this at home either, take my word for it. 0:08:12.840 --> 0:08:15.040 The lock will not open with gum in it, and 0:08:15.320 --> 0:08:19.360 COX two can't work with aspirin stuck in it. So 0:08:19.760 --> 0:08:23.360 by taking aspirin you don't stop the problem that's causing 0:08:23.400 --> 0:08:26.400 the pain, like the tight muscles in your scalp or 0:08:26.440 --> 0:08:30.520 the hammer damaged finger. But it does lower the volume 0:08:30.640 --> 0:08:33.079 on the pain signals going through your nerves to your 0:08:33.080 --> 0:08:37.920 brain and will prevent some inflammation from happening. This is 0:08:38.000 --> 0:08:41.600 not a targeted therapy. Aspirin doesn't know where to go 0:08:41.679 --> 0:08:44.800 in your body. When you take a tablet, it dissolves 0:08:44.800 --> 0:08:47.720 in your stomach or small intestine, and your body absorbs 0:08:47.720 --> 0:08:50.640 it from there into your bloodstream, which carries it through 0:08:50.679 --> 0:08:55.160 your entire body. Although it circulates pretty much everywhere, it 0:08:55.240 --> 0:08:59.559 only works where there are prostaglandins being made, including the 0:08:59.640 --> 0:09:03.560 area where it hurts. But the solution is not permanent. 0:09:04.120 --> 0:09:06.600 As with almost all chemicals, your body has a way 0:09:06.640 --> 0:09:10.360 of getting rid of aspirin. In this case, your liver, stomach, 0:09:10.400 --> 0:09:15.320 and other organs convert aspirin to salicylic acid. Your liver 0:09:15.480 --> 0:09:18.560 then sticks other chemicals onto the salisilic acid so that 0:09:18.600 --> 0:09:21.040 your kidneys can filter it out of your blood and 0:09:21.120 --> 0:09:24.840 send it out through your urine. The whole process takes 0:09:24.880 --> 0:09:27.280 about four to six hours, so you have to take 0:09:27.280 --> 0:09:29.559 another pill at that time if you want to keep 0:09:29.640 --> 0:09:35.800 the effect going. This is also a good but imperfect system. 0:09:37.240 --> 0:09:40.240 There are places in your body that need prostaglandins for 0:09:40.360 --> 0:09:44.840 various reasons. For example, in your stomach, a related enzyme 0:09:44.880 --> 0:09:48.480 COX one makes a prostaglandin that seems to keep your 0:09:48.480 --> 0:09:53.840 stomach lining nice and thick. Aspirin prevents that too, meaning 0:09:53.920 --> 0:09:57.400 that taking aspirin over time can cause your stomach lining 0:09:57.480 --> 0:10:01.360 to get thin, allowing your digestive juices to irritate it. 0:10:02.640 --> 0:10:06.079 This is probably the biggest reason why aspirin upsets stomachs, 0:10:06.640 --> 0:10:09.480 not only because it's an acid, as Bayer's chemists thought. 0:10:10.840 --> 0:10:13.640 There are other places in the body where prostaglandins have 0:10:13.679 --> 0:10:18.080 a job. In normal tissues, such as the blood. Some 0:10:18.200 --> 0:10:21.360 types of prostaglandins cause tiny particles in your blood known 0:10:21.400 --> 0:10:26.400 as platelets, to stick together in forming blood clots. By 0:10:26.440 --> 0:10:32.800 inhibiting prostaglandin production, aspirin slows down clot production. This can 0:10:32.880 --> 0:10:35.480 be bad, like if you have a bloody nose or 0:10:35.520 --> 0:10:38.800 a cut, in which cases you absolutely want a clot 0:10:38.840 --> 0:10:44.280 to form, so maybe avoid taking aspirin there. But blood 0:10:44.320 --> 0:10:47.800 clots can hurt us, as can happen in heart attacks 0:10:47.880 --> 0:10:51.240 when clots clog the blood vessels that carry oxygen through 0:10:51.320 --> 0:10:55.800 your hard working heart. That's why aspirin is recommended by 0:10:55.840 --> 0:10:58.960 healthcare providers to some people looking to prevent a heart 0:10:59.000 --> 0:11:03.240 attack or to recover from one. The way that aspirin 0:11:03.280 --> 0:11:06.240 lowers fevers also has something to do with its inhibition 0:11:06.280 --> 0:11:10.200 of prostaglandins, this time in the hypothalamus, which is a 0:11:10.200 --> 0:11:13.280 part of the brain that helps control body temperature, among 0:11:13.320 --> 0:11:17.880 other things. This one might be more complicated, though research 0:11:17.960 --> 0:11:23.000 is ongoing. But okayke anything you can take in. There 0:11:23.160 --> 0:11:26.680 is such thing as too much aspirin, and it can 0:11:26.760 --> 0:11:30.800 cause some unwonted side effects like bleeding or bruising if 0:11:30.880 --> 0:11:34.320 it prevents blood clots and upset or damage to the stomach. 0:11:35.440 --> 0:11:37.839 A risk of these side effects increases when you take 0:11:37.880 --> 0:11:42.360 aspirin alongside some other drugs like other painkillers, plus blood thinners, 0:11:42.400 --> 0:11:47.880 and many antidepressants. Additionally, aspirin is not recommended for bringing 0:11:47.880 --> 0:11:51.000 down the fever of kids with virus infections like the 0:11:51.040 --> 0:11:54.679 flu or chicken pox, because aspirin is associated with a 0:11:54.800 --> 0:12:00.280 deadly condition called rhye syndrome. In cases like those, drome 0:12:00.360 --> 0:12:03.199 causes brain damage, so aspirin should not be given to 0:12:03.280 --> 0:12:06.240 children and less directed by a healthcare provider for a 0:12:06.280 --> 0:12:12.079 specific condition. But for these reasons, scientists have found other 0:12:12.160 --> 0:12:15.079 chemicals related to aspirin that have some of its good 0:12:15.080 --> 0:12:20.079 effects and lack some of its bad ones. For example, abuprofin, 0:12:20.360 --> 0:12:23.920 sold under the brand names advil or motrin, and nepoxin 0:12:24.160 --> 0:12:27.200 or a leave can also treat pain, swelling and fever, 0:12:27.720 --> 0:12:30.280 but seem to have less of effect on platelets than 0:12:30.320 --> 0:12:33.840 aspirin does. All three of these are in a class 0:12:33.880 --> 0:12:38.640 called non steroidal antiinflammatory drugs because they decrease swelling, but 0:12:38.720 --> 0:12:41.960 they're not steroids, which are the most potent antiin inflammatories 0:12:42.000 --> 0:12:45.840 that we have. A Different class of medicines related to 0:12:45.920 --> 0:12:50.640 aspirin includes acetaminifin or tailanol, which decreases fevers and pain 0:12:50.880 --> 0:12:54.160 but doesn't affect inflammation or your stomach as much as 0:12:54.160 --> 0:12:58.480 nonsteroidal anti inflammatories do, and all of these options are 0:12:58.480 --> 0:13:03.680 generally safer for kids. Even with different options, asprin is 0:13:03.720 --> 0:13:07.160 still something of a wonder drug today. More research is 0:13:07.200 --> 0:13:08.880 being done to see if it might be able to 0:13:08.960 --> 0:13:13.240 help with other conditions, like some forms of cancer. As always, 0:13:13.360 --> 0:13:16.840 human bodies are complicated, so talk to a healthcare provider 0:13:16.880 --> 0:13:20.160 if you have any questions. But the next time you 0:13:20.160 --> 0:13:23.240 get out a hammer, think of those thousands of years 0:13:23.280 --> 0:13:27.160 of willow use and maybe set aside an aspirin or two. 0:13:27.480 --> 0:13:30.320 It's best to be prepared just in case you hit 0:13:30.400 --> 0:13:37.640 the wrong nail. Today's episode is based on the article 0:13:37.760 --> 0:13:40.600 asprin one oh one on HowStuffWorks dot com, written by 0:13:40.600 --> 0:13:43.880 doctor Lucas Hoffman. Brain Stuff is a production of iHeartRadio 0:13:44.000 --> 0:13:46.600 in partnership with HowStuffWorks dot com, and it's produced by 0:13:46.640 --> 0:13:50.080 Tyler Playing. For more podcasts from my heart Radio, visit 0:13:50.120 --> 0:13:53.440 the iHeartRadio app, Apple Podcasts, or wherever you listen to 0:13:53.480 --> 0:13:54.440 your favorite shows.