Walters-Fluroquinolones

Question 1

what do fluoroquinolones inhibit in gram negative bacteria? and in gram positive?

Answer 1

gram (-): inhibits DNA gyrase

gram (+): inhibits topoisomerase IV (separates DNA strands into 2 daughter cells)

Question 2

do 2nd generation FQs have better activity against S. pneumoniae?

Answer 2

no 3rd generation does

Question 3

what generation is ciprofloxacin and what 2 things does it do?

Answer 3

2nd gen.

1. decreases clearance of theophylline (broncho dilator) which leads to toxicity.
2. inhibits CYP3A4 and CYP1A2 which leads to increased levels of methadone & tizanidine leading to respiratory depression and hallucinations

Question 4

what generation is norfloxacin and what does it do?

Answer 4

2nd gen. it is least active and commonly used to treat urinary tract infections (UTI)

Question 5

what generation is ofloxacin?

Answer 5

2nd gen.

Question 6

what generation is gatifloxacin and what form is it in?

Answer 6

3rd gen. it is an ophthalmic solution

Question 7

what generation is levofloxacin and what does it do? side affects?

Answer 7

3rd gen. isomer of ofloxacin. has risk of prolonging Q-T interval which leads to an arrhythmia called “Tosades” in the elderly especially. also can lead to acute hepatitis and rare occurences of fatal events

Question 8

what generation is moxifloxacin and what does it do?

Answer 8

3rd gen. it is metabolized by the liver but can also lead to prolongation of Q-T interval, which will lead to arrhythmia

Question 9

what generation is besifloxacin and what does it do?

Answer 9

4th gen. for bacterial conjunctivitis due to susceptible organisms

Question 10

what are the general side effects of FQ’s?

Answer 10

photoxicity, arthropathy (damages growing cartilage), tendon rupture (black box warning), changes sugar levels (bad for diabetics) and CNS stimulation (convulsions and anxiety), nausea, peipheral neuropathy and diplopia

Question 11

why can FQ lead to nausea?

Answer 11

also stresses the bodies norma flora, which leads it form spores (C. difficile) along the GI tract and once all the bacteria are killed the C. dfficile hatch from spores and do not have any competition for nutrients so they grow in an unhealthy rate

Question 12

why would you want to avoid FQ interation with antacids and iron supplements?

Answer 12

they will chelate FQs and lead to decreased absorption

Question 13

what is the best fluroquinolone for gram negative activity?

Answer 13

Ciprofloxacin

Question 14

what is the least active of all the fluroquinolones?

Answer 14

Norfloxacin

Question 15

what medication has a narrow spectrum (cidal) against C. difficile and inhibits RNA polymerase?

Answer 15

Fidaxomicin