PHARM_ANTIMICROBIALS

Question 1

MOA daptomycin

Answer 1

rapidly disrupts bacterial cell membranes

-results in depol. & loss of memb. pot’l and K+ efflux

Question 2

how is daptomycin administered?

Answer 2

IV infusion

Question 3

which antibiotic is primarily bound to serum albumin?

Answer 3

daptomycin

Question 4

what is the notable adverse effect on daptomycin?

Answer 4

muscle pain or weakness

Question 5

what are the indications for daptomycin?

Answer 5

1. aerobic gram + bacteria (MRSA, strep, enterococcus)
2. complicated skin & soft tissue infections
3. MSSA and MRSA bacteremia (including right-sided endocarditis)

Question 6

Linezolid MOA

Answer 6

inhibits protein synthesis via binding to the 23S RNA on 50S RNA Ribosomal subunit

Question 7

what is linezolid indicated for?

Answer 7

very serious VRE infections

MRSA & S. epidermis

Question 8

how does resistance develop to linezolid?

Answer 8

point mutation in 23S RNA (emerging resistance w./ enterococcal & S. Aureus)

Question 9

how is linezolid administered?

Answer 9

oral (100% absorption) and parenteral

Question 10

what are the most common adverse effects of linezolid?

Answer 10

diarrhea
optic & peripheral neuropathy
headache
N/V
(possible pseudomembranous colitis)

Question 11

what are some important drug interactions with linezolid?

Answer 11

non-selectiive inhibitor of MAO ( don’t give with drugs metabolized by MAO like pseudophedrine)

Question 12

which antimicrobial drug has these adverse effects:
myelosuppression associated w/ therapy beyond 2 wks
-optic and peripheral neuropathy, lactic acidosis

Answer 12

linezolid

Question 13

the oral suspension of linezolid contains _________which you should warn to pts with phenylketonuria

Answer 13

aspartame

Question 14

In addition to being a 1st line TB drug, rifampin is an effective antibiotic for G+ cocci including _____________

Answer 14

MRSA (usually in como w/ beta-lactam or vancomycin)

• also used to eradicate staph. in nasal carriers
• prophylactically for household members exposed to meningitis caused by meningococci or H. influenzae

Question 15

clindamycin MOA

Answer 15

macrolide, inhibition of protein synth. by binding to 50S subunit of ribosome

Question 16

what is the MLS phenotype?

Answer 16

Macrolide-Lincosamide(clindamycin) -Streptogramin resistance phenotype encoded by ERM gene

Question 17

clindamycin is effective for which bugs?

Answer 17

anaerobes-both G+ (MRSA, GAS) & and G- (actinomyces, peptostreptococci)

Question 18

how is clindamycin administered?

Answer 18

orally

Question 19

which antibacterial drug doesnt penetrate the CSF or intracellular, but does cross the placenta & is found in breast milk?

Answer 19

clindamycin

Question 20

what are the adverse effects of clindamycin?

Answer 20

Pseudomembranous colitis from C. difficile (treat w/ metronidazole or vancomycin)

• GI
• Hypersensitivity

Question 21

Mupirocin MOA

Answer 21

inhibits protein & RNA synthesis by binding reversibly to staphylococcal isoleucyl tRNA synthetase

Question 22

what are the therapeutic uses of clindamycin?

Answer 22

Bacteroides fragilis (outside CNS)
Prophylactic coverage when pt is allergic to penicillin (MSSA and MRSA of soft tissue)

Question 23

how is mupirocin administered?

Answer 23

topical (little systemic absorption w/ topical use)

Question 24

what are the indications for mupirocin?

Answer 24

topically in impetigo

eliminating MRSA from carriers

Question 25

how does bacitracin work?

Answer 25

inhib. bacterial cell wall synth
- inhib. movement of peptidoglycan building blocks of cell wall from inside to outside the cell membrane by inhib. dephosphorylation of the isoprenyl pyrophosphate carrier protein

Question 26

what is bacitracin used for?

Answer 26

topically for gram positive cocci & bacilli (used w/ neomycin and polymyxin B)

Question 27

what is the major toxicity of bacitracin w/ parenteral use?

Answer 27

severe nephrotoxicity