Another high yield USMLE Step 1 pharmacology topic is antiplatelet drugs. This video provides an overview of the pharmacology of cardiovascular drugs, with a focus on antiplatelet drugs. It covers the mechanism of action of aspirin, and other antiplatelet drugs. The adverse effects of aspirin are also discussed.
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00:00 anti-platelet drugs are a very important 00:02 concept for the usmle step one 00:04 do you know their mechanism of action 00:06 are you familiar with their important 00:08 side effects 00:09 let's take a look let's begin with a few 00:12 important concepts regarding platelets 00:14 platelets are formed from megakaryocytes 00:17 and they have a lifespan of around 8 to 00:19 10 days 00:20 platelets have two important storage 00:22 granules alpha granules 00:24 and dense granules alpha granules are 00:27 more 00:27 numerous they store fibrinogen one will 00:31 bring factor 00:32 and glycoprotein 2b3a dense granules 00:36 release their contents when platelets 00:38 are aggregated 00:39 and their contents aid in platelet 00:42 aggregation 00:43 dense granules store adp 00:46 atp catecholamines serotonin and calcium 00:50 glycoprotein 2b3a acts as a receptor for 00:54 fibrinogen 00:55 on the surface of platelets antiplatelet 00:59 drugs are divided into four different 01:01 classes 01:02 cyclooxygenase inhibitors adp inhibitors 01:06 glycoprotein 2b3a inhibitors and 01:09 phosphodiesterase inhibitors 01:11 let's begin with cyclooxygenase 01:13 inhibitors this class includes 01:15 aspirin and triflusal aspirin 01:18 is an irreversible inhibitor of the 01:20 enzyme coxone 01:22 or prostaglandin8 synthase it inhibits 01:25 the synthesis of thromboxane 01:27 a2 thereby inhibits platelet aggregation 01:31 common side effects of aspirin include 01:34 nausea 01:35 heartburn slightly increased risk of 01:38 intracranial hemorrhage 01:39 and abdominal or epigastric pain 01:42 if you give enterocoated aspirin the 01:45 abdominal 01:46 or gi side effects of aspirin can be 01:49 decreased 01:50 however since it is an irreversible 01:52 inhibitor the action of aspirin 01:55 will last the whole lifespan of the 01:58 platelet which is eight to ten days 02:01 adp inhibitors include clopidogel or 02:04 plavix 02:05 pressure gel ticagrelor anticlopidine 02:09 all these clopidogel and presudrail are 02:11 pro drugs 02:12 which need to be activated by cytochrome 02:14 p450 system in the liver 02:16 they are given as adjuncts to aspirin 02:20 in patients undergoing percutaneous 02:23 coronary intervention 02:24 or angioplasty with stent placement 02:28 common side effects include diarrhea and 02:30 skin rash with clopidogel and procedure 02:33 t-copeline may cause neutropenia 02:35 thrombocytopenia 02:36 and ttp or thrombotic thrombocytopenic 02:39 purpura 02:41 the next class of antiplatelet drugs is 02:43 glycoprotein 2b3a inhibitors 02:46 they include abscisimam terophiben 02:49 and eptiphepatite of these abscessimap 02:52 is a monoclonal antibody that binds to 02:54 the glycoprotein 2b3a receptor 02:57 whereas sterophyben and eptifibertide 03:00 they mimic 03:00 part of the structure of fibrinogen and 03:03 compete with fibrinogen 03:05 on binding to the glycoprotein 2b3a 03:09 receptor 03:10 side effects include thrombocytopenia 03:12 glycoprotein 2b3a inhibitors are given 03:15 in patients who are undergoing 03:16 percutaneous coronary interventions like 03:18 angioplasty with stent placement the 03:21 last class of anti-platelet drugs 03:24 is phosphodiesterase inhibitors these 03:26 drugs in 03:27 erase the camp levels within the 03:29 platelets and 03:30 include dipyridamole and cilostazol 03:33 silostazole is metabolized by cytochrome 03:36 p450 enzyme system 03:38 in the liver hence its dose needs to be 03:41 decreased 03:41 in patients who are concomitantly being 03:44 treated with cytochrome p450 inhibitors 03:47 like omeprazole 03:48 so let's recap the important points 03:51 there are four classes of antiplatelet 03:53 drugs 03:54 cyclooxygenase inhibitors adp inhibitors 03:57 glycoprotein 2b inhibitors and 04:00 phosphodiesterase inhibitors 04:03 aspirin is an irreversible inhibitor of 04:05 the enzyme cox 1 04:07 or prostaglandin h synthase aspirin is 04:10 given along with copyright gel in 04:11 patients undergoing percutaneous 04:13 coronary 04:14 interventions the glycoprotein 2b3a 04:17 inhibitors include abscissimam 04:19 eptiphypatite anterophyben ticlopidine 04:23 is associated with ttp or thrombotic 04:26 thrombocytopenic purpura 04:28 phosphodiester is inhibitors raise 04:31 intraplatelet 04:32 camp levels thanks for watching 04:35 if you are looking for a great resource 04:36 to solidify your usmle knowledge 04:38 check out achievable giveaway is an 04:41 online course with a comprehensive and 04:42 searchable textbook 04:44 and it has thousands of quizzes which 04:46 will help you build 04:47 and test your knowledge link is in the 04:49 description 5:23 NOW PLAYING Passaging Cells: Cell Culture Basics Thermo Fish
