Anti-Microbials

Question 1

list the 14 anti pseudomonals

Answer 1

FQs: cipro and levofloxacin

monobactam: aztreonam
carbapenems: all 4 (*imipenem and meropenem)
cephalosporins: ceftazidime, cefepime

Piperacillin, carbenicillin

aminoglycosides: gentamicin, tobramyicn, amikacin

colistin

Question 2

rx for outpatient w/ no recent AB use

Answer 2

macrolide (G+, H flu, A) or doxy (G+,G-, A)

Question 3

preferred macrolide for H flu

Answer 3

azithromycin

erythromycin is ineffective against H flu, causes GI distress

Question 4

moa of macrolides

Answer 4

inhib 50S

Question 5

macrolide toxicities

Answer 5

prolonged QT (monitor when pts taking other drugs like Class Ia or III AARD)

Question 6

macrolide drug interactions

Answer 6

inhibit CYP3A4, increased effects from many drugs like warfarin

not as much inhibiton from azithromycin

Question 7

other effects of macrolides

Answer 7

anti inflammatory

Question 8

moa of doxycycline

Answer 8

30S inhibitor

Question 9

doxy toxicities (4)

Answer 9

prolonged QT (monitor w/ other drugs)

photosensitivity (UV converts drug to immunoreactive form)

tooth discoloration

teratogenic- accumulates in bone and interferes with developement

Question 10

PK issues w/ doxy

Answer 10

chelates cations and becomes insoluble

avoid taking w/ Ca, Mg, Al, Fe, Zn

Question 11

rx for outpatient w/ comorbidities or recent AB use

Answer 11

FQ (G+/G-/A)

or B-lactam (G+/G-) and macrolide

avoid same drug as previously used

Question 12

major respiratory FQs

Answer 12

levofloxacin, moxifloxacin, gemifloxacin

cipro is not effective against strep pneumo so not used

Question 13

FQ moa

Answer 13

DNA synthesis inhibiton- targets DNA gyrase

Question 14

FQ toxicities

Answer 14

prolonged QT, nephrotoxicity (interstitial nephritis), tendon rupture

avoid in pregnancy if there is an alternative

Question 15

FQ drug interactions

Answer 15

interact w/ NSAIDs- cause CNS problems like tremors, anxiety, insomnia, seizures

Question 16

recommended first line B lactams to be given w/ macrolide)

Answer 16

penicillin (amoxicillin) or cephalosporins (ceftriaxone, cefpodoxime, cefuroxime)

Question 17

B lactam toxicities (4)

Answer 17

Type I allergy (true allergy, IgE mediated): anaphylaxis, hypotension, bronchospasm, angioedema

Type II (IgG): slower, inflammation, urticaria, fever

Type IV: rare but could be fatal Stevens Johnson syndrome (toxic epidermal necrolysis)

nephrotoxicity (mostly penicilins, early cephalosporins)

Question 18

worst B lactam for pregnancy

Answer 18

imipenem

Question 19

rx for inpatient non ICU

Answer 19

FQ

or B lactam plus macrolide

Question 20

recommended B lactam inpatient non ICU

Answer 20

cefotaxime or ceftriaxone (IV/IM)

or ampicillin (IV/oral)

Question 21

rx for inpatient ICU

Answer 21

B lactam and azithromycin

or B lactam and FQ

both require B lactam

Question 22

B lactam moa

Answer 22

disrupt peptidoglycan in cell wall

Question 23

which 2 bugs must be covered in ICU?

Answer 23

strep pneumo and legionella

Question 24

which B lactam does not produce hypersensitivity

Answer 24

aztreonam

Question 25

ICU recommendations

Answer 25

Aztreonam + FQ has best evidence (avoids B lactam hypersensitivity)

Question 26

Rx when worried about pseudomonas or MRSA

Answer 26

for pseudomonas: B lactam + FQ or B lactam + aminoglycoside + FQ for MRSA: Vancomycin or linezolid

Question 27

recommended B lactams for pseudomonas

Answer 27

piperacillin +tazobactam cefepime imipenem/meropenem

Question 28

carbapenem toxicities

Answer 28

seizures- inhibit GABA receptors in brain (increased firing due to less hyperpolarization)

Question 29

anti pseudomonal FQ

Answer 29

levofloxacin cipro is but not against strep pneumo so not used empirically

Question 30

aminoglycoside moa

Answer 30

inhibit 30S, selective for G-

Question 31

aminoglycoside toxicities

Answer 31

ototoxicity- damage hair cells, often permanent nephrotoxicity (acute tubular injury to glomerulus, PCT, collecting duct)- usually reversible

Question 32

aminoglycoside and pregnancy

Answer 32

category D- not recommended

Question 33

vancomycin moa/ category

Answer 33

glycopeptide- disrupts cell wall

Question 34

linezolid moa/ category

Answer 34

oxazolienones- inhib 50S

Question 35

vancomycin toxicities

Answer 35

nephrotoxicity, ototoxicity these are rare w/ vanc alone, should be avoided w/ other toxic drugs like aminoglycosides Red man syndrome- mast cell histamine release -can be avoided w/ diluted dose over an hour w/ antihistamines

Question 36

linezolid toxicities

Answer 36

myelosuppression and thrombocytopenia

Question 37

linezolid drug interaction

Answer 37

inhibit breakdown of serotonin- interact w/ SSRIs and can cause serotonin syndrome (fever, agitation, tremor, sweating)

Question 38

Rx w/ MSSA and Non MDR pseudomonas

Answer 38

piperacillin/tazobactam cefepime levofloxacin imipenem or meropenem anti pseudomonal and anti staph (G+)

Question 39

Rx w/ MRSA and non MDR pseudomonas

Answer 39

MRSA- Vanc or linezolid ``` antipseudomonal- piper/tazobactam cefepime or ceftazidime levofloxacin imipenem or meropenem aztreonam ```

Question 40

Rx for MSSA and MDR pseudomonas

Answer 40

B lactam anti pseudomonal (piper/tazo, cefipime or ceftazidime, imipenem or meropenem, aztreonam) and non B lactam anti pseudomonal (levo, amikacin or gentamicin or tobramicin)

Question 41

rx for MRSA and MDR pseudomonas

Answer 41

``` B lactam anti pseudomonal and non B lactam anti pseudomonal (same list + maybe colistin) and MRSA coverage w/ vanc and linezolin ```

Question 42

colistin moa

Answer 42

cell membrane inhibitor by binding to LPS

Question 43

colistin toxicities (3)

Answer 43

nephrotoxicity- mostly seen at high doses and not as bad as AGs muscle weakness- interference w/ NMJ signaling peripheral nerve damage, paresthesia

Question 44

clindamycin moa

Answer 44

50S inhib

Question 45

targets for clinda

Answer 45

G+ and G- anaerobes, esp for the aspiration pneumonias: bacteroides, prevotella, fusobacterium, peptostreptococcus

Question 46

clinda toxicities

Answer 46

pseudomembranous colitis C diff superinfection