Antibiotics IV

Question 1

Prototype FQ

Answer 1

Ciprofloxacin

Question 2

What class of drugs MOA is bactericidal agents that inhibit one of the two topoisomerase II enzymes (DNA gyrase or topoisomerase IV)

Answer 2

Fluoroquinolones

Question 3

Therapeutic uses of FQs

Answer 3

Broad spectrum: Used to treat common urogenital, respiratory and GI infections caused by aerobic G- microbes; prophylaxis for anthrax

Question 4

Adverse effects of FQs

Answer 4

1) Tendon rupture
2) Confusion, somnolence, visual disturbances in elderly
3) Some members of this class prolong QT interval
4) CDAD (ciprofloxacin)

Question 5

This drug class can increase plasma levels of theophylline and warfarin. The oral dose can also be reduced when taken with multivalent cations. What class is this? (Hint: Not Tetracyclines)

Answer 5

FQs

Question 6

This drug is a prodrug that is inactive until it is reduced in anaerobes by either of 2 enzymes- pyruvate-ferredoxin oxidoreductase (PFOR) or nitroreductase

Answer 6

Metronidazole- bactericidal in anaerobic bacteria (and sensitive protozoa)

Question 7

Drug of choice for CDAD

Answer 7

Metronidazole

Question 8

_____________ in combination with tetrcycline and bismuth subsalicylate to eradicate H.pylori in patients with peptic ulcer disease

Answer 8

Metronidazole

Question 9

Adverse rxns of metronidazole

Answer 9

1) Headache, GI disturbances, metalic taste, dark-red-brown urine
2) CYP3A4 substrate- Disulfiram-like rxn with ethanol (nausea and vomiting), inhibits metabolism of warfarin

Question 10

Sulfonimide:

Answer 10

Sulfamethoxazole

Question 11

MOA of Sulfamethoxazole

Answer 11

Bacteriostatic: Folic acid inhibitor; structural analog of PABA-prevents DNA replication

Question 12

Adverse RXNs of Sulfamethoxazole

Answer 12

1) Kernicterus in newborns
2) Hypersensitivity rxns -SJS
3) Hemolytic anemia- G6PD deficiency

Question 13

What drug prevents reduction of dihydrofolate to its active form ultimately blocking formation of A,G,T. Competitive inhibitor of dihydrofolate reductase (DHFR)

Answer 13

Trimethoprim

Question 14

What is bactericidal (synergistic) combo that results from inhibition of sequential steps of folate biosynthesis

Answer 14

Co-trimoxazole (TMP/SMX) (1:5)

Question 15

Therapeutic uses of Co-trimoxazole (TMP/SMX)

Answer 15

UTIs, Pneumocystitis jirovicii pneumonia (AIDS, cancer, organ transplant), and otitis media infections

Question 16

Major side effect of Co-trimoxazole (TMP/SMX)

Answer 16

Myelosuppression-AIDS patients unusually susceptible

Question 17

Name a cyclic lipopeptide

Answer 17

Daptomycin

Question 18

What drug has a Ca2+ dependent insertion of its lipophilic tail into the plasma membrane to form an ion-permeable channel that permits efflux of intracellular K+

Answer 18

Daptomycin- Bactericidal: Membrane depolarization, inhibits DNA, RNA, protein synthesis.

Question 19

T/F: Daptomycin is active only against G+ bacteria

Answer 19

True- cannot pierce G- membrane

Question 20

What drug is inactivated by surfactant

Answer 20

Daptomycin

Question 21

Adverse rxn of daptomycin

Answer 21

myopathy (measure CPK)

Question 22

Name polymyxins

Answer 22

Colistin, polymyxin B

Question 23

What drug binds to negatively-charged LPS in outer membrane of G- bacteria and hydrophobic tail has a detergent like effect increasing permeability?

Answer 23

Polymyxins (Colistin)

Question 24

T/F: Colistin (cationic) sulfate is used for topical and oral (GI) use while colistimethate (anionic) is used for parenteral use; prodrug of colistin

Answer 24

TRUE

Question 25

Therapeutic use for polymyxins

Answer 25

Treatment last resort for serious MDR G- bacterial infections (ESKAPE organisms)

Question 26

Adverse rxns of polymyxins

Answer 26

Reversible nephrotoxicity and neurotoxicity (only parenterally, not absorbed topically)