Infection: Quinolones

Question 1

What quinolones are effective in the treatment of uncomplicated urinary-tract infections?

Answer 1

Nalidixic acid and norfloxacin and ofloxacin.

Question 2

All quinolones must be used with consideration to what important safety information?

Answer 2

1. Can prolong QT interval.
2. Can induce seizures.
3. Can cause tendon damage.

Question 3

What are the three indications for norfloxacin?

Answer 3

1, uncomplicated UTI

2. Chronic relapsing lower urinary-tract infections.
3. Chronic prostatits

Question 4

Ciprofloxacin is active against what bacteria?

Answer 4

Both +ve and -ve but it is particularly active against Gram-negative bacteria, including Salmonella, Shigella, Campylobacter, Neisseria and Pseudomonas.

Question 5

Can Ciprofloxacin be used for pneumococcal pneumonia?

Answer 5

NO.

Ciprofloxacin has only moderate activity against Gram-positive bacteria such as Streptococcus pneumoniae and Enterococcus faecalis; it should not be used for pneumococcal pneumonia. It is active against Chlamydia and some mycobacteria.

Question 6

What is ofloxacin used for?

Answer 6

1. UTI
2. LRTI
3. Gonorrhoea
4. Non-gonococcal urethritis and cervicitis.

Question 7

How do levofloxacin and ciprofloxacin differ in terms of activity?

Answer 7

Levofloxacin is active against Gram-positive and Gram-negative organisms. It has greater activity against Pneumoccoi than ciprofloxacin.

Question 8

Many Staphylocci are resistant to quinolones and therefore the use of quinolones in what hospital infections should be avoided?

Answer 8

MRSA

Question 9

Which of the following drugs/drug classes is NOT active against P. aeruginosa?

Fluoroquinolones (not moxifloxacin)
Piperacillin/tazobactam 
Cefepime
Kanamycin
Ceftobiprole 
Ceftazidime

Answer 9

Aminoglycosides in general ARE active against P. aeruginosa but Kanamycin is not.

Question 10

Third and fourth generation quinolones - such as gemifloxacin and moxifloxacin - selectively inhibit what?

Answer 10

3rd and 4th gen quinolones selectively inhibit topoisomerase IV, though they also have an effect on topoisomerase II (but less than first and second gen quinolones).

Enhanced inhibition of topoisomerase IV means 3rd and 4th generation quinolones have greater gram-positive coverage than their predecessors.

Question 11

Which of the following statements is false?

Quinolones may worsen the symptoms of myasthenia gravis.

Quinolones are bacteriostatic.

Quinolones work by disrupting cell division - via topoisomerase.

Quinolones may cause QT prolongation, most notably with moxifloxacin.

Answer 11

Quinolones are bacteriocidal

Question 12

Caffeine enhances the effects of ciprofloxacin and should therefore be avoided during quinolone therapy.

True or False?

Answer 12

This is false.

The effects of ciprofloxacin are not enhanced, but the effects of caffeine ARE enhanced when the two taken together.

For this reason, caffeine should be avoided in patients taking ciprofloxacin.

Question 13

Risk of seizures is increased when quinolones are taken with:

Paracetamol
Lamotrigine
NSAIDs
Triptans 
Digoxin

Answer 13

The risk of seziures is increased when quinolones such as ciprofloxacin are taken with NSAIDs.