ABx for staph and strep

Question 1

What is the MOA of Daptomycin?

Answer 1

rapidly disrupts bacterial cell membranes

Question 2

What are the results of the MOA of daptomycin?

Answer 2

depolarization and loss of membrane potential and K+ efflux

Question 3

resistance to daptomycin?

Answer 3

rare due to bactericidal (none known)

Question 4

When should daptomycin be administered?

Answer 4

infused 1x/day after hemodialysis

Question 5

why can daptomycine not be given IM?

Answer 5

direct muscle toxicity

Question 6

What is significant about the metabolism of daptomycin?

Answer 6

90% bound to albumin

Question 7

How is daptomycin eliminated? dose adjustments necessary?

Answer 7

renal; dosage adjustment for renal deficiency only

Question 8

What are ADEs with daptomycin? How can they be monitored?

Answer 8

muscle pain/weakness=> serum creatine phosphokinase elevations

Question 9

Are there drug interactions with daptomycin?

Answer 9

none with P450s

caution w/ -statin use

Question 10

What are the Tx uses for daptomycin?

Answer 10

aerobic gram +; MDR gram +; MSSA, MRSA bacteremia; skin/soft tissue infections

Question 11

What disease and why should daptomycin not be used in?

Answer 11

pneumonia as surfactant antagonizes daptomycin

Question 12

What is the MOA of oxazolidinones-linezolid?

Answer 12

inhibits protein synthesis by binding to 23S RNA on 50 ribosomal subunit

Question 13

oxazolidinones-linezolid has static effects on which bugs? cidal effects?

Answer 13

static=> staph, entero

cidal=> strep

Question 14

How does resistance occur with oxazolidinones-linezolid?

Answer 14

point mutation in 23S RNA (entero and S. aureus)

Question 15

What are the FDA approved indications for oxazolidinones-linezolid?

Answer 15

PRSA; MRSA; resistant s. epi; Enteroccus faecium and faecalis; reserve for serious VRE infections

Question 16

How should oxazolidinones-linezolid be administered?

Answer 16

orally or parenteral but food delays absorption=> supplemental doses after hemodialysis

Question 17

How is oxazolidinones-linezolid metabolized?

Answer 17

non enzymatic oxidation with 2 inactive metabolites=> no CYP interactions

Question 18

Elimination of oxazolidinones-linezolid?

Answer 18

both non-renal and renal mechanisms

Question 19

ADEs for oxazolidinones-linezolid?

Answer 19

well tolerated but common are diarrhea, headache, nausea, vomiting; myelosuppression in Tx longer than 2 wks

Question 20

other than myelosuppresion, what else is associated with Tx longer than 2 wks with oxazolidinones-linezolid?

Answer 20

reversible thrombocytopenia, anemia, neutropenia; optic and peripheral neuropathy; lactic acidosis

Question 21

What is a warning patients must receive with oral admin of oxazolidinones-linezolid?

Answer 21

contains aspartame so PKU patients need warning

Question 22

What are the associated DDIs with oxazolidinones-linezolid?

Answer 22

non selective inhibitor of MAO so caution used=> HTN from decreased breakdown

Question 23

Rifampin MOA

Answer 23

inhibits DNA dependent RNA polymerase

Question 24

What is the most active anti-leprosy drug at present time?

Answer 24

rifampin

Question 25

What is the MOA for clindamycin?

Answer 25

inhibition of protein synthesis by binding to 50S subunit of ribosome

Question 26

When is clindamycin not affected?

Answer 26

when given with erythromycin

Question 27

Is clindamycin static or cidal?

Answer 27

either depending on concentration

Question 28

resistance to clindamycin?

Answer 28

slowly due to decreased affinity of drug for the ribosome

Question 29

What is the Tx use for clindamycin?

Answer 29

anaerobes (G+ & G-); peptostreptococci, actinomyces; bacteroides fragillis; G+ cocci (MRSA, group A strep)

Question 30

clindamycin absorption

Answer 30

nearly complete orally and acid stabile but delayed by food

Question 31

clindamycin distribution

Answer 31

widely into bone and abscesses=> NOT in CSF or intracellular

Question 32

clindamycin in pregnancy

Answer 32

crosses placenta and found in breast milk

Question 33

clindamycin metabolism

Answer 33

liver to inactive forms

Question 34

clindamycin dose adjustment

Answer 34

patients with liver disease but NONE with renal disease

Question 35

clindamycin excretion

Answer 35

bile and urine but not removed by hemodialysis

Question 36

ADEs of clindamycin

Answer 36

pseudomembranous colitis from clostridium difficile; GI disturbances; hypersensitivity rashes

Question 37

What should you treat pseudomembranous colitis from clindamycine use?

Answer 37

metronidazole or vancomycin

Question 38

When can clindamycin be used prophylactically?

Answer 38

patient is allergic to penicillin w/ associated strep and staph infections like MRSA, MSSA

Question 39

clindamycin and pyrimethamine treat what specific subset of patients

Answer 39

toxoplasmosis in patients with AIDS

Question 40

What is the MOA for mupirocin?

Answer 40

inhibits protein and RNA synthesis=> binds reversibly to staph tRNA synthetase

Question 41

mupirocin cidal or static

Answer 41

concentration dependent

Question 42

mupirocin Tx uses

Answer 42

G+ (staph and strep); MRSA; impetigo

Question 43

Absorption of mupirocin

Answer 43

topically absorption is limited and quickly inactivated

Question 44

What is significant about the vehicle for mupirocin delivery in ointment?

Answer 44

polyethlyene glycol may cause renal failure

Question 45

What is the MOA for bacitracin?

Answer 45

inhibits bacterial cell wall synthesis by blocking inside to out dephosphorylation of carrier protein

Question 46

Tx uses for bacitracin

Answer 46

G+ cocci and baccili

Question 47

What is an ADE with parenteral use?

Answer 47

nephrotoxicity

Question 48

What is bacitracin typically found with in ointment?

Answer 48

neomycin and polymyxin B