AbxinterferingwithFolatesynthesisC

Question 1

Disruption of the folate pathway is generally what in single agent therapy?

Answer 1

Bacteriostatic

Question 2

What are the 2 enzyme targets for bactericidal folate antagonists ?

Answer 2

Dihydropteroate sythetase, Dihydrofolate reductase

Question 3

Folate is a cofactor for what?

Answer 3

Transfer of 1-carbon groups ad electrons in intracellular synthesis and degradation reduction

Question 4

Sulfonamides target bacteria that are used in what pathway?

Answer 4

PABA pathway

Question 5

T/F- Sulfonamides are bacteriostatic against gram +/- bacteria?

Answer 5

TRUE

Question 6

What are the 3 major groups of sulfonamides?

Answer 6

Oral absorbable, Oral nonabsorbable, Topical agents

Question 7

What are the oral absorbable sulfonamides?

Answer 7

Sulfadiazine- uti, uncomplicated malaria. Sulfadoxine, Sulfisoxazole- otitis media, UTI, chloroquine resistant malaria, drug resistant malaria, and toxoplasma gendii
Sulfamethoxazole- URI, UTI, prophylaxis and tx of p carinii (HIV)

Question 8

What is the nonabsorbable agent and its uses?

Answer 8

Sulfasalazine, Delayed release in RA, UC, enteritis

Question 9

What is sulfasalazine not indicated for?

Answer 9

Infectious disease inflammations

Question 10

What are the topical agents are their uses?

Answer 10

Sodium sulfacetamide,Ophthalmic, Chlamydia trachorra,/ silver sulfadiazine ñ burn infection prophylaxis

Question 11

What is the most common cause of preventable blindness worldwide? How is it treated?

Answer 11

Chlamydia trachoma,Sodium sulfacetamide

Question 12

What special populations need to be considered for sulfa use?

Answer 12

Pregnant women and neonates

Question 13

What is trimethoprim?

Answer 13

Competitive inhibitor of dihydrofolic acid reductase, Similar to sulfonamides but more potent and has increased penetration to the prostate

Question 14

What are indications for trimethoprim?

Answer 14

Community acquired UTI or prophylaxis of UTI, RARELY used ALONE

Question 15

What 2 agents create bactrim?

Answer 15

Sulfamethoxazole+ trimethoprim

Question 16

What are the clinical uses of bactrim?

Answer 16

Pneumocystis carinii, bacterial diarrhea, prophylaxis- UTI, PCP, peritonitis

Question 17

What category of drugs inhibit DNA topoisomeroses?

Answer 17

Quinolones

Question 18

What category of drugs inhibit DNA dependant RNA polymerase?

Answer 18

Directly: rifampin, Indirectly: nitrofurantoin

Question 19

Are quinolones cidal or static?

Answer 19

Bactericidal

Question 20

Which quinolone has gram ñ coverage w/ moderate gram + activity?

Answer 20

Ciprofloxacin

Question 21

Which quinolone has excellent gram ñ coverage w/ improved gram +

Answer 21

Levofloxain, moxifloxacin

Question 22

Which quinolone has continued gram +/- coverage with increased anaerobic coverage?

Answer 22

Trovafloxacin

Question 23

Which atypical pneumonia organisms and intracellular pathogens are also covered by quinolones?

Answer 23

Atypical: Chlamydia pneumo, mycoplasma pneumo, Intracellular: legionella, mycobacteria tb, mycobacteria avium complex

Question 24

In general, how often are quinolones used and what are their clinical uses?

Answer 24

VERY frequently, UTI, sinusitis, mycobacterial infections, bacterial diarrhea, soft tissue/bone/joint infections, gonococcal and chlamydial, pneumonia, post-exposure prophylaxis for anthrax

Question 25

Which quinolone is FDA restricted to life or limb threatening infections?

Answer 25

Trovafloxacin

Question 26

Why should fluoroquinolone not be used for routine URIs or skin/soft tissue infections?

Answer 26

We want to prevent resistance! Save these for last to minimize resistance

Question 27

Quinolones are widely distributed throughout the body, including what typically underpenetrated area?

Answer 27

Prostate

Question 28

What are the most common ADRs of quinolones? Rare?

Answer 28

N/V/D, Seizure w/use of NSAIDs, blood dyscrasias, irreversible peripheral neuropathy

Question 29

Which quinolone is approved to treat mild- moderate CAP d/t multi-drug resistant strep pneumo?

Answer 29

Gemifloxacin

Question 30

What is metronidazole (flagyl) spectrum of activity?

Answer 30

Anaerobic and protozoan infections. -amebiasis, trichomonias, cns infections, c. diff, and h. pylori

Question 31

Can metronidazole be given in pregnancy?

Answer 31

NOT 1st TRIMESTER, category B in 2/3

Question 32

With what drug interaction can metronidazole cause disulfiram-like rxns? What is this rxn?

Answer 32

ETOH! Flushing, HA, N/V, sweating, tachycardia

Question 33

When is nitrofurantoin cidal? Static?

Answer 33

High concentrations= cidal Low concentrations= static

Question 34

What is nitrofurantoinís biggest indication and why?

Answer 34

UTI -- d/t increased concentrations in the urine

Question 35

What pt population should you avoid nitrofurantoin in?

Answer 35

Elderly

Question 36

What are indications of polymyxin B? what is its spectrum of activity?

Answer 36

Gram negative Topical prep, antibiotic ointments, washes for wounds, surgery prep

Question 37

Why is polymyxin B limited to topical use?

Answer 37

High nephro/neurotoxicity

Question 38

Can you give polymyxin B IV or IM?

Answer 38

Only in life or death situations