Exam 2: Fluoroquinolones

Question 1

What are the 6 drugs in the fluoroquinolone class?

Answer 1

Ciprofloxacin, ofloxacin, Levofloxacin, moxifloxacin, gatifloxacin, and gemifloxacin

Question 2

What is the MOA of fluoroquinolones?

Answer 2

Inhibition of DNA grasses prevents the relaxation of positively supercoiled DNA that is required of normal transcription and replication.

• Inhibition of Topo IV interferes with separation of replications chromosomes to daughter cells
• Bactericidal

Question 3

What is the spectrum of fluoroquinolones?

Answer 3

Primarily effective against G- rods, with good G+ coverage.

-Moxi and gemifloxacin are effective against anaerobes.

Question 4

Which fluoroquinolone is used to treat UTIs?

Answer 4

Ciprofloxacin

Question 5

How are fluoroquinolones excreted?

Answer 5

Renally, but can be blocked by probenecid

Question 6

Which fluoroquinolone is used to treat prostatitis?

Answer 6

Ofloxacin

Question 7

What are the adverse effects of fluoroquinolones?

Answer 7

GI disturbance, prolonged QT interval, Cartilage erosion, tendon rupture, and photosensitivity

Question 8

What are the contraindications of fluoroquinolones?

Answer 8

Pregnancy, nursing women, and children under 18

Question 9

What is the MOA of metronidazole?

Answer 9

It is a prodrug that is non-enzymatically reduced by reacting with reduced ferredoxin. Metabolites are taken up into bacterial DNA and form unstable molecules.
-Bacteriocidal

Question 10

What is the spectrum of metronidazole?

Answer 10

Potent antibacterial activity against G+ and G- ANAEROBES

Question 11

What is metronidazole indicated for?

Answer 11

Anaerobic or mixed intrabdominal infections , vaginitis, RTI, pseudomembranous colitis (vanco first choice), and endo carditis
-Also part of the combo therapy for H. Pylor

Question 12

What are the adverse reactions to metronidazole?

Answer 12

Disulfiram like reaction, disgeusia (metallic taste), GI disturbance, CNS and PNS toxicity, and hypersensitivity

Question 13

What bacteria is responsible for most community acquired infections?

Answer 13

E. Coli

Question 14

What G+ bacteria causes about 10-15 % of UTIs?

Answer 14

Staphylococcus saprophyticus

Question 15

What bacteria are responsible for catheter associated UTIs?

Answer 15

Proteus, klebsiella, Serratia, and pseudomonas

Question 16

What are the 3 important properties of exclusive UTI drugs?

Answer 16

1) renally excreted ( if not, the drug is not going where it needs to go to treat the UTI)
2) Achieve high urinary concentrations, but not therapeutic concentrations anywhere else in the body. Cidal in the urine, concentration dependent
3) Required an acidic environment to be activated

Question 17

What are the 2 exclusive UTI drugs?

Answer 17

Nitrofurantoin and Methanamine

Question 18

What is the MOA of Nitrofurantoin?

Answer 18

Damaged bacterial DNA - it is a prodrug reduced in bacterial cells to an intermediate that can attack ribosomal proteins, DNA, and metabolism molecules

Question 19

What is the spectrum of Nitrofurantoin?

Answer 19

G+, G-, E. Coli, S. Pyogenes, Citrobacter, klebsiella, enterobacter, salmonella, shigella, and Indole positive proteus.

Question 20

What bacteria are resistant to Nitrofurantoin?

Answer 20

Most proteus and and pseudomonas

Question 21

When should Nitrofurantoin not be used?

Answer 21

If creatinine clearance is less than 50mL/min. Antibiotic will not reach sufficient levels in urine for antibacterial activity

Question 22

What patient education should you give when prescribing Nitrofurantoin?

Answer 22

It turns the urine brown

Question 23

What are the adverse side effects of Nitrofurantoin?

Answer 23

Nausea, vomiting, diarrhea, allergic reactions, hepatocellular damage, hemolytic anemia (in G6PD deficiency), pulmonary fibrosis (with chronic usage), and neurological disorders

Question 24

What are the contraindications of Nitrofurantoin?

Answer 24

Pregnancy between 38-42 weeks (because babies G6PD status is not yet known) less than one month age, impaired renal function, and allergy.

Question 25

What is the MOA of methenamine?

Answer 25

Taken orally, this prodrug decomposes to formaldehyde and ammonia in the acid medium fo the urinary tract.

-Bacterial resistance to formaldehyde does not develop

Question 26

What is the spectrum of methenamine?

Answer 26

Nearly all bacteria are sensitive but those that increase the pH of the urine inhibit the release of formaldehyde (proteus).
Combine with a weak organic acid such as hippuric acid

Question 27

What are the toxicities associated with methenamine?

Answer 27

Essentially no toxic because little decomposition takes place in the body until it appears in the acidic urine.
Possible to have mild GI distress or allergic reaction

Question 28

What are the contraindications of methenamine?

Answer 28

• Hepatic insufficiency: conversion to formaldehyde releases ammonia which needs to be converted to urea in the liver, which cannot be done in hepatic deficiency. Can lead to hepatic encephalopathy
• Renal insufficiency: Low urine output