Antibitoics IV: Nucleic Acid Membrane Disruptors

Question 1

Prototype fluoroquinolone

Answer 1

Ciprofloxacin

Question 2

Fluoroquinolone MOA

Answer 2

Direct inhibition of DNA synthesis by binding directly toDNA-topoisomerase complexes; bactericidal

Question 3

Boxed warnings for fluoroquinolones

Answer 3

Neuromuscular blockade (contraindicated in myasthenia gravis)
May occur together: tendon rupture, seizures, peripheral neuropathy)

Question 4

Other side effects of fluoroquinolones

Answer 4

Prolonged QT interval
Hypoglycemia
Photosensitivity

Question 5

Fluoroquinolone contraindications

Answer 5

Pts under 18
Myasthenia gravis

Question 6

Nitroimidazole drug

Answer 6

Metronidazole

Question 7

Metronidazole MOA

Answer 7

Bactericidal prodrug that is converted to active form in anaerobes by ferredoxin reductase cycle
Produces free radicals that cause lethal DNA strand breaks

Question 8

Nitroimidazoles are narrow spectrum, only active against ____

Answer 8

Anaerobes

Question 9

Adverse reactions of nitromidazoles

Answer 9

Dark urine
Peripheral neuropathy
Metallic taste

Question 10

Boxed warning for nitroimidazoles

Answer 10

Carcinogenic; only use when necessary

Question 11

Nitroimidazole drug interaction

Answer 11

Alcohol (flushing, tachycardia, headache, nausea)

Question 12

Folic acid is essential for synthesis of ___ and ____

Answer 12

Nucleic acids and amino acids

Question 13

Most bacteria must _____ folate

Answer 13

Synthesize (can’t absorb it)

Question 14

Antifolates act on which enzyme?

Answer 14

Dihydrofolate reductase (DHFR)

Question 15

Sulfonamide MOA

Answer 15

Structural analog of PABA component of folic acid
Competitive inhibitor of dihydropteroate synthase in bacteria which blocks formation of dihydropteroic acid
Bacteriostatic

Question 16

Sulfonamide drug

Answer 16

Sulfamethoxazole

Question 17

Adverse reactions for sulfonamides

Answer 17

Kernicterus in neonates
Hypersensitivity rash
Hemolytic anemia in pts with G6PD deficiency

Question 18

Trimethoprim MOA

Answer 18

Competitive inhibitor of bacterial DHFR

Question 19

Adverse reactions of trimethoprim

Answer 19

Bone marrow suppression if pt has folate deficiency
Hyperkalemia

Question 20

Co-trimoxazole (Bactrim) is a combination of:

Answer 20

Trimethoprim and sulfamethoxazole

Question 21

Co-trimoxazole is very broad spectrum, effective against aerobic G+ and - bacteria and ____

Answer 21

MRSA
Opportunistic fungal pathogens

Question 22

Cyclic lipopeptide prototype drug

Answer 22

Daptomycin

Question 23

Cyclic lipopeptide MOA

Answer 23

Inserts lipophilic tail into plasma membrane to cause K+ effluent, leading to depolarization and kills the bacteria

Question 24

Daptomycin is only effective against G + or - bacteria?

Answer 24

G+

Question 25

Daptomycin adverse reactions

Answer 25

Myopathy (monitor CK)
Eosinophilia pneumonia

Question 26

Polymyxin prototype drug

Answer 26

Colistin

Question 27

Polymyxin MOA

Answer 27

Hydrophobic tail has detergent-like effect that disrupts outer and inner membranes to increase cell permeability

Question 28

Polymyxins can be administered ____ or ______

Answer 28

Topically (Neosporin) or by IV

Question 29

Polymyxins adverse reactions

Answer 29

None for topical use
Nephrotoxicity and neurotoxicity with IV use