ABX review -Table 1 Flashcards
Which abx is drug of choice for treating enterococcus?
Ampicillin
Which ABX is least effective against MRSA?
Clindamycin
Which abx are 1st gen cephalosporins?
Cephalexin(Kaflex), cefazoli, cefaclor
What is GAS?
Group A streptococcus, step pyogenes
What test can quickly decipher Staph. aureus from Staph epidemidids?
Coagulase test, S.Aureus is coag positive, while staph epidemidis is coag negative
What is GBS?
Group B streptococcus, strep agalactiae, Beta hemolytic
What are some gram negative rods?
Enterobacteriacea, pseudomonas, acinetobacter, morazella, xanthomonas, bordatella, legionella, haemophilis influenzae
What are SPACE organisms?
Serratia, pseudomonas, acinetobacter, citrobacter, enterobacter, need double coverage of abx d/t virulence
What are some gram negative anaerobes?
Bacteroides, Prevotella, Fusobacterium, Clostridium(+), actinomyces, peptostreptococcus(+)
What is traditional PCN used to Tx?
Syphilis and GBS in pregnancy
Aminopcns are what drugs?
amoxicillin and ampicillin
What are aminopcn’s best at covering?
Gram+, specifically enterococci, listeria, strep, H.pylori
What are the antistaphylococcal pcns?
Methicillin, oxacillin, nafcillin(IV only), dicloxacillin, cloxacillin,
What do antistaphylococcals cover?
Additional staph coverage, with strep, Gram +, NOT MRSA
When switching from Nafcillin(IV) to a PO equivalent, what do you rx?
Dicloxacillin
What are the Antipseudomonal pcns?
Piperacillin, Ticarcillin
How does piperacillin and ticarcillin contrast?
Piper covers enterococcus and Ticar impairs platelet aggregation, ticar is also IV
What are some Beta-lactamase organisms?
Staph, H.flu, Klebsiella, B.Fragilis
What is unasyn?
Ampicillin/Sulbactam
When taking a pt off of IV unasyn what PO pcn/betalactamase do you use?
Augmentin aka. Amoxicillin/clavulanate (PO)
What is the potential cross sensitivity of using a cephalosporin in a pt allergic to other beta lactams?
3-5%
What don’t cephalosporins cover?
Enterococcus(gram+)
What are the first generation cephalosporins?
Cefazolin, cephalothin, (PO)>cephalexin, cephradine, cefadroxil
What do you know about the Proteus species?
Gram -, enterobacteriacia, HUMAN PATHOGEN, “buring chocolate” odor, isolated from urine, wounds, ears and bacteremic, Not a nice species
When are 1st generation cephalosporins used?
For surgical prophylaxis, staph and strep infections and UTI, d/t their E.coli, proteus, strep, MSSA and klebsiella coverage
When taking a pt off of IV cefazolin, what PO 1st gen can you send them home with?
Cephalexin(PO)
What are the second generation cephalosporins?
Cefaclor, cefprozil, lorcarbef, cefamandole, cefurozime,
What are the cephamycins?
Cefoxitin and cefotetan (cefo)
How do 2nd gen cephalosporins compare to cephamycins?
Cephamycins have anaerobic coverage and so used for CAP, Abd. infections, PID, and UTI ….2nd gen cephs
What are the 3rd generation cephalosporins?
Cefpodoxime, ceftibuten, cefdinir, cefixime, cefditoren, IV>Cefotaxime, ceftriaxone, ceftizoxime, ceftazidime,
Which 3rd gen ceph has activity against pseudomonas?
Ceftrazidime
What is different from 3rd gen cephs compared to 2nd gen?
3rd gen- has better gram neg coverage, and covers spirochetes(borrielia, T.pallidum(syphilis))
What does 4th gen ceph treat?
Nosocomial infections(pseudomonas) and febrile neutropenia
What are the 5th gen cephs?
Ceftaroline fosamil and ceftaroline tazobactam
What is updated about 5th gen cephs that is different from other cephs?
Covers MRSA and s.pneumoniae,
Aztreonam covers?
Most gram negatives(pseudomonas included), no gram pos coverage
What is ceph is comparable to aztreonam?
Ceftazidime(3rd gen), d/t similar side-chains, so has cross reactivity potential and similar gram neg coverage
What do macrolides cover?
Strep, atypicals, whooping cough(pertussis), neisseria, H.flu,
Of the macrolides, which one has the fewest drug interactions?
Azithromycin, whereas clarithromycin interacts with statins and erythromycin has most interactions
When switching from IV to PO macrolides which do you choose?
Azithromycin(iv) to erythromycin(PO)
Does ampicillin/sulbactam(unasyn) cover pseudomonas?
Nope, Zosyn(pipercillin/taxo), cefepime and primaxin (imipenem-cilastin) do though
What ABX are considered to have a narrow spectrum of coverage?
Penicillin, oxacillin/nafcillin, cefazolin, cephalexin/cephradine, aztreonam,
Penicillins: renal clearance EXCEPT?
Oxacillin and nafcillin
Sulfonamides compete for albumin with:
Bilirrubin: given in 2°,3°T, high risk or indirect hyperBb and kernicterus in premies
Warfarin: increases toxicity: bleeding
Beta-lactamase (penicinillase) Suceptible
Natural Penicillins (G, V, F, K) Aminopenicillins (Amoxicillin, Ampicillin) Antipseudomonal Penicillins (Ticarcillin, Piperacillin)
Beta-lactamase (penicinillase) Resistant:
Oxacillin, Nafcillin, Dicloxacillin 3°G, 4°G Cephalosporins Carbapenems Monobactams Beta-lactamase inhibitors
Penicillins enhanced with:
Clavulanic acid & Sulbactam (both are suicide inhibitors, they inhibit beta-lactamase)
Aminoglycosides (against enterococcus and psedomonas)
Cephalosporines: renal clearance EXCEPT
Cefoperazone & Cefrtriaxone (bile)
2°G Cephalosporines: none cross BBB except
Cefuroxime
3°G Cephalosporines: all cross BBB except
Cefoperazone bc is highly highly lipid soluble, so is protein bound in plasma, therefore it doesn’t cross BBB.
Cephalosporines are “LAME“ bc they do not cover this organisms
L isteria monocytogenes
A typicals (Mycoplasma, Chlamydia)
M RSA (except Ceftaroline, 5°G)
E nterococci
Drugs that cause disulfiram-like reaction: Colorado Cannabis Consumers Got Marihuana legalized
C efotetan C efoperazone C hlorpropamide G riseofulvin M etronidazole
Cefoperanzone: all the exceptions!!!
All 3°G cephalosporins cross the BBB except Cefoperazone.
All cephalosporins are renal cleared, except Cefoperazone.
Disulfiram-like effect
Against Pseudomonas:
3°G Cef taz idime (taz taz taz taz)
4°G Cefepime, Cefpirome (not available in the USA)
Antipseudomonal penicillins
Aminoglycosides (synergy with beta-lactams)
Aztreonam (pseudomonal sepsis)
Covers MRSA:
Ceftaroline (rhymes w/ Caroline, Caroline the 5°G Ceph), Vancomycin, Daptomycin, Linezolid, Tigecycline.
- Covers VRSA:
Linezolid, Dalfopristin/Quinupristin
DEMECLOCYCLINE is ?
tetracycline that’s not used as an AB, it is used as tx of SIADH to cause Nephrogenic Diabetes Insipidus (inhibits the V2 receptor in collecting ducts)
Phototoxicity: Q ue S T ion?
Q uinolones
Sulfonamides
T etracyclines
p450 inhibitors:
Cloramphenicol, Macrolides (except Azithromycin), Sulfonamides
Macrolides SE
Motilin stimulation, QT prolongation, reversible deafness, eosinophilia, cholestatic hepatitis
Bactericidal
beta-lactams (penicillins, cephalosporins, monobactams, carbapenems), aminoglycosides, fluorquinolones, metronidazole.
Baceriostatic
tetracyclins, streptogramins, chloramphenicol, lincosamides, oxazolidonones, macrolides, sulfonamides, DHFR inhibitors.
Pseudomembranous colitis
Ampicillin, Amoxicillin, Clindamycin, Lincomycin.
QT prolongation:
macrolides, sometimes fluoroquinolones