Antibacterial drugs (12 Q's on the test)

Question 1

Sulfonamides: -cidal or -static

Answer 1

-static

Question 2

Sulfonamides MOA

Answer 2

inhibit Dihydropteroate synthase (inhibits folate synthesis and RNA/DNA/aa synthesis)

Question 3

what are some dose unrelated toxicities of sulfonamides

Answer 3

hypersensitivity rxns (Stevens Johnson-mild to serious rashes)
photosensitivity
acute kidney injury (sulfamethoxazole)

Question 4

what are dose related toxicities of sulfonamides?

Answer 4

crystalluria (if not well hydrated)
GI
anemia
Kernicterus (encephalopathy in neonates)

Question 5

clinical uses of sulfonamides

Answer 5

UTIs
pneumocystis jirovecii in HIV/AIDS
prophylaxis: meningitis, burns, wounds

Question 6

Trimethoprim: -static or -cidal

Answer 6

-static

Question 7

Trimethoprim inhibits

Answer 7

Dihydrofolate reductase (we have this enzyme too but works better with prokaryotes)

Question 8

What is a good drug to use in combination with trimethoprim (synergism)?

Answer 8

sulfamethoxazole (both are static but become cidal together)

Question 9

clinical uses of trimethoprim

Answer 9

urinary, respiratory infections
prostatis
pneumocytis jarovecii in AIDS
MRSA***(know)

Question 10

Which works better for pseudomonas aeruginosa? Sulfonamides or Trimethoprim?

Answer 10

Sulfonamides

Question 11

Quinolones: -static or -cidal

Answer 11

-cidal

Question 12

Quinolones MOA

Answer 12

Inhibit DNA gyrase and Topoisomerase IV

Question 13

Quinolones inhibit DNA gyrase. What is DNA gyrase’s function?

Answer 13

induces transient double strand breaks in DNA to relieve torsional stress in front of replication fork

Question 14

Quinolones have a rapid excretion in the urine but what is the one exception?

Answer 14

Moxifloxacin

Question 15

3 resistant mechanisms to quinolones?

Answer 15

1) DNA gyrase or Topo IV mutations
2) Increased efflux
3) altered porins

Question 16

Quinolones are well absorbed orally but one can be inhibited by drinking with milk since it is inhibiting by cations++

Answer 16

Cipro

Question 17

Nitrofurantoin MOA

Answer 17

nitro-reduction to form DNA damaging oxygen radicals

Question 18

Nitrofurantoin: -static or -cidal

Answer 18

-static but can be -cidal with high doses

Question 19

Clinical use of nitrofurantoin

Answer 19

UTI’s (single dose usually)

Question 20

Nitrofurantoin is well absorbed … and has … levels in the urine. One possible toxicity is … which is reversible

Answer 20

orally
high
pulmonary fibrosis

Question 21

T/F: Metronidazole is a pro-drug

Answer 21

true

Question 22

Metronidazole: -static or -cidal

Answer 22

-cidal

Question 23

Metronidazole requires … … activation

Answer 23

anaerobic reductive

Question 24

Metronidazole MOA

Answer 24

anaerobic nitro-reduction to metabolites that bind to and perturb DNA function

Question 25

Resistant mech. to metronidazole

Answer 25

reduced activation

Question 26

Clinical uses of metronidazole

Answer 26

anaerobic infections- gram positive and gram negative; some protozoal infections

Question 27

Toxicities of metronidazole

Answer 27

metallic taste

disulfiram-like effect (nausea,vomiting)

peripheral neuropathy

central neurotoxicity: dizziness, vertigo, convulsions, ataxia

Question 28

4 important resistant mechanisms to beta-lactams

Answer 28

1) beta-lactamases (gram + and gram -)
2) Altered PBP’s (MRSA->MecA->PBP2a)(lower affinity for beta-lactams)
3) Altered Porins (gram neg)
4) Increased efflux (gram neg)

Question 29

Clinical uses of PCNs

Answer 29

Group A streptococcus
Streptococcus pneumoniae (pediatric)
Endocarditis, meningitis
STD's (+probenecid)
UTI's

Question 30

Are Penicillins dose or time dependent?

Answer 30

Time-dependent