Clinical | Infectious Disease | Antibiotic Ladder | @OnlineMedEd

an online meded the videos are free you can learn what you need to learn but to get the most out of the course access the premium content sign up now to get access when you begin studying antibiotics what's really hard is to figure out what antibiotic to use under what condition at the very end of this lecture we're going to review each of the different infectious disease diagnoses are going to see a lot on medicine and you're going to have to memorize their empiric coverage and that's the problem most of the time the antibiotic you pick is based on empiric evidence it's really hard to derive which antibiotic you should choose so for life you're going to see a lot of the same things get used over and over and over again on the test though they're going to expect you to know the usual antibiotics you're supposed to use for each of these diagnoses but then they're going to throw in a wild card some reason why they can't have that one or it's going to sound like a regimen that's close but really isn't so we're going to start off by going through the antibiotic ladder that is how you might try to derive some antibiotic regimens based on the organism you're going after realizing I'm not going to cover all antibiotics and finish with the stuff you just have to memorize so let's start off by going through gram positive and gram negatives first and this is the antibiotic ladder it begins with penicillin so called the first antibiotic and it was a good antibiotic had gram-positive coverage gram-negative coverage it worked it was the first thing we had it saved a lot of lives the problem with penicillin is though that most organisms have become resistant to penicillin with pen v or pen Begay pen G or pen VK and the only thing you're going to use penicillin to treat is essentially syphilis so we've come up with other versions of penicillin the first thing we tempted to tackle with staph aureus and we use the methicillin x' now methicillin is not ever used in practice it is in the lab only and you'll probably have heard of em RSA but we'll get to that in just a minute these actually have a name but I can call them the methicillin because they're used to treat one thing and that is staph aureus that is not methicillin-resistant ox clocks like locks and naf naf sewing is the one you're going to see use the most Nath's tone is used for staph aureus that is not resistant to methicillin and since we're talking about it the thing that comes up on the ground positive column is mr sa methicillin-resistant staph aureus you don't have to remember the D allah-allah thing but just know that penicillin binding proteins have changed such that regular penicillins don't work and you need something special and not something special is vancomycin they do want to take just to brief me to talk about vancomycin first I want you to notice that vancomycin is not broad-spectrum it covers mr si when you pick mega myosin you are saying I'm treating Mercer if you see mersa you should treat with vancomycin it coagulates positive clusters is staph you don't know that it's mr si until it grows on the thing with the methicillin there and it continues to grow showing you that it's methicillin-resistant oftentimes mr si is so prevalent we start with mr s a coverage on the test be careful they want you to go as far down the ladder as possible starting penicillin and working your way up so all you've got is staph aureus you probably want to pick a methicillin unless you have a good indication for vancomycin and this is the antibiotic ladder so you want to start as low down on the rung as possible and climb your way up only as necessary so if you can't use vancomycin for whatever reason going off the top of the ladder is linezolid and lenez's really good choice it's got an oral form and an IV form but it is really expensive so the most important thing about this ladder is that you should not start at the top of the ladder you should start as low down as possible for mrs a it's going to vancomycin and then lanessa let it banks not available on the gram negative side we have some penicillin variants and that's ampicillin and amoxicillin now you may be frustrated by this because amoxicillin you know you can use to treat strep throat and strep throat you're trading strep yet I'm going to tell you that amoxicillin episode should be used for gram-negative coverage if you're going after organisms that are gram-negative you should go for a Moxon Epis Ilyn and the way you get without empirics the way you get these expanded to get a little more coverage is the beta-lactamase inhibitor this makes them broad-spectrum they have gram positive gram negative but notice they don't touch em RSA and bacillus eiv lots of zelans the PIO amoxicillin clavulanic happening so back down give you broad-spectrum but that's not broad enough because just as there was Mrs a and the positive side so to do you have a resistant virulent organism on the ground negative side and that is Pseudomonas to treat so Damona so you need a stronger version of penicillin and it's going to be Piper so there's another one in here but I never use it so pepper someone is the one you want to remember and it's beta-lactamase inhibitor taser back down pip Tazo is zosyn and zosyn is used all the time in the hospital it's used all the time in the hospital because it has gram positive gram negative and anaerobic coverage the only thing it doesn't get is Mrs a and fungus so if you just have to reach for something because you don't know what's going on and they're sick you put given people in my potato and that's okay in that situation where they're really sick you don't know what the bug is because you're going after everything is if you don't treat it they'll die but really what you're saying is when you say I want pip Tazo you're covering Pseudomonas if you're not going to cover Pseudomonas specifically don't reach for pip Tazo pick something else and very similarly to a nasal lid if you need more coverage they can't take the sewing carbapenems carbapenems are very good gram-negative coverage they also cover Pseudomonas and this lies to a little bit more than usual and that is to say that pip Tazo and cover pens are essentially the same on the ladder but I want you to realize that people are going to reach for pip Tazo much more often they are carbapenems so in this world of gram positive and gram negatives there's one last piece and that is the cephalosporins the foundation in which this ladder is built and in being very particular about where I'm placing these blocks because I want you to see that third-generation cephalosporins are going to grab gram positive and gram negative all right if we map out gram-positive coverage you'll see the first and second generation cephalosporins have a lot of gram-positive coverage and begins to taper off in the third and you essentially should not use fourth generation cephalosporins program positive coverage and then the exact opposite is true for a gram negative coverage is very little the first two generations the third generations begin to pick it up and the fourth generation cephalosporins are essentially the things you use to cover Pseudomonas when you can't cover anything else theft as and ceftriaxone third-generation cephalosporins cefepime fourth generation cephalosporins and the ones over here you very rarely use these are going to be skin antibiotics like cefazolin used to treat cellulitis and do prophylaxis for surgery ceftriaxone and seft as you're going to have good penetration gram positive and negative coverage for generation cephalosporins cefepime should be used only for Pseudomonas I want you to know that there is a fifth generation cephalosporin but you're not going to use it because it's mr-s a coverage and it's way off the ladder you're never going to use that until you actually get the cultures and sensitivities it's really important so we pointed out Mr SA and Pseudomonas and so we're going to pick those things for empiric coverage of diseases that might be caused by these bugs in general what you want to do is be as targeted as possible if you get a culture then you have sensitivities and you pick the narrow spectrum antibiotic the cheapest one in addition if someone's really sick just go abroad which is why everybody gets pip Tazo and mecha myosin when they're sepsis and they're really sick you're getting everything so that's okay escalate quickly deescalate slowly and if they're ill go abroad at the end of the day be as narrow spectrum as you can based on cultures and sensitivities and it's okay to start off broad but vente biotics with a simple you would need the video so there's a little bit more there's also the fluoroquinolones which I want to talk about and I like to use the baseball mnemonic that is to say in baseball you have to go through first base to get to second to get the third to come home so that anyone on third base has already gone through first and second base that is to say the correlation of the fluoroquinolone generations the first generations have the unique properties the second generation includes the properties of the first generation because you had to go through first base and likewise the third generation fluoroquinolones possess the second and first because they had to go around the diamond in order to get there now you've probably heard people mention the respiratory fluoroquinolone or the urinary fluoroquinolone well I Got News for you the entire cardiac output goes through the lungs so every fourth point alone is a respiratory fluoroquinolone and most of the excretion is done by the urinary system so every fluoroquinolone is a urinary fluoroquinolone so what are they talking about when they say that what they're talking about is this and as you do with the gram-negative and gram-positive coverage the first generation fluoroquinolone is ciprofloxacin and cipro has great gram-negative coverage but it doesn't do anything for gram positives and since cipro is the urinary fluoroquinolone you might not be surprised to realize that urinary tract infections are primarily gram-negative the third-generation fluoroquinolone is moxifloxacin in moxifloxacin being a third-generation cephalosporin has gram-negative coverage but it also picks up some gram positive coverage the others don't moxifloxacin can be used to treat pneumonia as the respiratory for quite alone because it is capable of covering organisms that cause pneumonia and psyche generation and Oliver ever really use let's leave a full on Stinson some adjunct soft skin tissue infections but what I want you to see is the fluoroquinolones moxie should be used for treating ammonia's cipro should be used for treating gram-negative infections whereas moxie can cover gram negatives but you don't want to give the unnecessary coverage so stick with the lowest on the latter in this case the lowest the baseball toilet anti robes you want you can get with pip Tazo but you sometimes want to be more targeted than that and this is my advanced organizer remembering what to use where you've got two options metronidazole clindamycin metronidazole is groin and belly abdomen vagina growing belly metronidazole only if it's anywhere else clindamycin to an anaerobic coverage clindamycin for any we're not the belly or the groin metronidazole if you're going after anaerobic coverage the vagina and in the abdomen now there's definitely more to it than this you know it's more complicated than this and we're not going to talk about a lot of things we're not talking about fungus and we're not talking about some other antibiotics that you'll come across that I just don't use that often the reason why I'm doing that is to keep this simple because you're going to pull these antibiotics often in order to get the right answer so let's go through as I said I would the empiric coverage for the diseases you're going to see the most often it's going to be community choir pneumonia healthcare-associated pneumonia meningitis UTI and cellulitis for a community-acquired pneumonia you have a couple of options if what he talked about it the first one is Moxie moxifloxacin can be given oral or IV and so it's very tempting to use Moxie because you're given my IV first you have an aural equivalent right away but you're going to breed fuller quinolone resistance to certain organisms so if you can avoid that avoid it you can also use ceftriaxone and is it two myosin we didn't talk about the macrolides but you should memorize ceftriaxone epicentre myosin or moxie or as if out on its own it goes something like this if the person is going to come into the hospital in these IV medications you should give them the combination of tracks on and azithromycin if the person is ambulatory can go home just give them oral is it through myosin Moxie is the equivalent for subtraction and is it through myosin so it can be given IV or Pio moxifloxacin ends up being abused by physicians in the sense that it is poor antibiotic stewardship so for the test it is always wrong in an age cap you're covering for two things you're covering for EM RSA and Pseudomonas knowing that the logical choice is going to be Bank and pip Tazo meningitis just have to memorize it it's ceftriaxone at two grams a higher dose than usual vancomycin plus minus steroids plus minus antis own for the m3 level every meningitis get steroids for the m3 level only immunocompromised patients get episode or on that in the brain inflammation lecture but it's ceftriaxone and vancomycin and steroids and only ampicillin if you have immuno compromised for UTI you've got a couple of options and this gets frustrating amoxicillin is good as we said gram-negative coverage or you can use nitro for your antonin or you use bathroom which I method from cell phone or you can use ceftriaxone or you can use cipro so how do you pick locks of cell and if you're pregnant that's your fair and tone if you're a woman bathroom only if you don't have renal failure ceftriaxone is IV so it's given to people who are septic with really bad pilo and cipro is reserved for ambulatory pyelonephritis you're going to see this misuse all the time but that's the test sir cipro is only used for ambulatory pile-up ceftriaxone is used for inpatient management of pyelonephritis these others can be used essentially interchangeably unless you have renal failure where you can't use our method prim sulfa unless you're pregnant where you should use amoxicillin as the first line answer an insight Linus becomes really tough because there's a lot of outpatient inpatient management but what I want you to learn is the cellulitis you suspect to be mrs a since we want mrs a coverage we should use vancomycin but other options exist because this requires intravenous forms you can also use clinda or bactrim knowing that it is not unreasonable to treat with the first or second generation cephalosporin going after strep and then only using these guys when that's failed because then it's probably mr sa okay let's go through one more time antibiotic latter stay as low as you possibly can look out for nasa and thank you - and lanessa lid for staph coverage look for ampicillin or moxa sill and foreground negatives and pip Tazo for Pseudomonas Cobra pendants also Pseudomonas cefepime fourth generation cephalosporin also Pseudomonas clindamycin everywhere else at renautas all gut and groin and then you just have to memorize the list of antibiotics that go with each condition and kind of know a little bit about why you could can't choose one over the other and that is the antibiotic ladder become a better doctor subscribe now to get access to our premium content

Channel: OnlineMedEd

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Keywords: OnlineMedEd, USMLE, NBME, COMAT, PANCE, Step 2, Infectious Disease, Antibiotic Ladder, Antibiotics, Antibiotic Resistance, Cephalosporins, Penicillin, MRSA, Gram Positive, Gram Negative, FOAMed, #foamed, MedEd, Clinical Education, Whiteboard Teaching

Id: rhFZ-yPfy2U

Length: 18min 34sec (1114 seconds)

Published: Tue Mar 01 2016