Small Group: Antimicrobials

Question 1

1. State the class, mechanism, main spectrum of action and main adverse reactions of penicillin.

Answer 1

penicillin
beta-lactam
cell wall inhibition 
Strep, syphilis, most entero; some gram neg.
hypersensitivity

Question 2

1. State the class, mechanism, main spectrum of action and main adverse reactions of Cephalexin.

Answer 2

1st gen cephalosporin
cell wall inhibition
Staph, strep, E. coli, Proteus
Hypersensitivity

Question 3

1. State the class, mechanism, main spectrum of action and main adverse reactions of ceftriaxone.

Answer 3

3rd generation cephalosporin
cell wall inhibition
gram (-) aerobes, not pseudamonas; strep
hypersensitivity- biliary sludge

Question 4

1. State the class, mechanism, main spectrum of action and main adverse reactions of vancomycin.

Answer 4

glycopeptide
cell wall inhibition
Staph and strep
Nephrotoxicitiy, ototoxicity, marrow toxicity, infusion related histamine release

Question 5

1. State the class, mechanism, main spectrum of action and main adverse reactions of doxycycline.

Answer 5

tetracycline
protein synthesis inhibition
Staph, Lyme, rickettsia, anaplasma
teeth and bones, GI, photosensitivity

Question 6

1. State the class, mechanism, main spectrum of action and main adverse reactions of tobramycin.

Answer 6

amino glycoside
protein synthesis inhibition
gram (-) aerobes including pseudamonas
nephrotocity, otovestibular toxicity

Question 7

1. State the class, mechanism, main spectrum of action and main adverse reactions of TMP-SMX.

Answer 7

antifolate
anti-metabolite
Staph, gram (-) aerobes, nocardia, pneumocystis
folate deficiency, skin rashes, cytopenia

Question 8

1. State the class, mechanism, main spectrum of action and main adverse reactions of ciprofloxicin.

Answer 8

quinolone
NA inhibition
gram (-) aerobes, including pseudamonas
photo toxicity, cartilage, tendonopathy, neuropathy

Question 9

1. State the class, mechanism, main spectrum of action and main adverse reactions of azithromycin.

Answer 9

macrolide
protein synthesis inhibition
Strep, mycoplasma, legionella, chlamydia, pertussis
GI

Question 10

1. State the class, mechanism, main spectrum of action and main adverse reactions of metronidazole.

Answer 10

nitroimidazole
nucleic acid synthesis inhibition
anaerobes
peripheral neuritis, metallic taste

Question 11

Additional (lofty) goals for application in the LO.

Answer 11

2. Outline and defend a rationale to be used for antimicrobial prescription in particular instance.
3. Apply these basic concepts to clinical scenarios so that you can understand how a clinician decides on a particular antimicrobial agent for initial empiric therapy and subsequent definitive therapy.

Question 12

List factors to consider when prescribing.

Answer 12

pt allergies and intolerance
possible adverse effects
drug interactions
local susceptibility
dosing schedule/complexity
absorption/perfusion/excretion
site of infection
risk of C.diff
formulary status/ drug availability 
pregnancy
requires drug monitoring?

Question 13

What is the DOC in a patient with strep pharyngitis with anaphylaxis to penicillin?

Answer 13

macrocodes (erythromycin or azithromycin)

Question 14

What is the DOC of MRSA? (CA-MRSA)

Answer 14

TMP- SMX, clindamycin, minocycline and linezolid

methicillin susceptible: dicloxacillin

Question 15

What are the choice drugs for an uncomplicated UTI? Why can’t you use moxi for a UTI?

Answer 15

TMP/Sulfa (increasing E.coli resistance) or nitrofurantoin
ceftriaxone can be a good managing option of pyleonephritis (misses enterococci but can given IM) although considered psuedamonas coverage

broken down in liver doesn’t get to bladder, note quinolones also chelate with quinolone

Question 16

What bacteria do you worry about when there is bowel perforation?

Answer 16

1. enterococci
2. aerobic GNR
3. anaerobes