Fluoroquinolones

Question 1

Fluoroquinolones

Answer 1

Ciprofloxacin
Levofloxacin
Gemifloxacin
Moxifloxacin
Norfloxacin
Gatifloxacin

Question 2

Fluoroquinolones - MoA

Answer 2

Inhibition of DNA topoisomerase II (DNA gyrase) + IV, preventing DNA replication and separation of chromosomes. DNA gyrase is responsible for the breaking and resealing reactions. Type IV topoisomerase is responsible for separating the DNA of daughter chromosomes once DNA replication is completed (this process is called decatenation).

Question 3

Topoisomerase II primary bacteria

Topoisomerase IV primary bacteria

Answer 3

II - Gram negative

IV - Gram positive

Question 4

Fluoroquinolones binds to which subunit of DNA gyrase?

Answer 4

A subunits

Question 5

Ciprofloxacin - Clinical use

Answer 5

Primarily gram-negative bacteria

Gonocci, chlamydia, P. aeruginosa, UTI, Prostatitis, pelvic inflammatory disease

Bacterial diarrhea (Caused by Campylobacter, Salmonella, Shigella, Yersinia entereocolotica)
Travelers diarrhea
(E. coli)

Intra-abdominal infections, febrile neutropenia

Bone and joint, skin, eye infection

Anthrax (Bacillus anthracis)

Question 6

Levofloxacin - Clinical use

Answer 6

Both gram-negative and gram-positive bacteria

Bronchitis

Comm-acq pneumonia

UTI, prostate, bone and joint, skin, eye infections

Question 7

Gemifloxacin, Moxifloxacin - Clinical use

Answer 7

Commuity acquired pneumonia (Chlamydia pneumoniae, K. pneumoniae, Mycoplasma pneumoniae, Legionella pneumpophila)

Sinusitis (Caused by pneumococci, H. influenzae or M. catarrhalis)

Bronchitis (Caused by pneumococci, H. influenzae or M. catarrhalis)

Drug resistant tuberculosis. Active against mycobacterium avium

Bacterial conjunctivitis (Moxifloxacin)

Question 8

Norfloxacin - Clinical use

Answer 8

UTI’s

Question 9

Gatifloxacin - Clinical use

Answer 9

Bacterial conjuctivits

Question 10

Fluoroquinolones - Special considerations

Answer 10

Should be taken 2 hours before/after foods with Ca, Fe, Mg, Zn (Because fluoroquinolones, like tetracyclines, can chelate these divalent and trivalent cations, forming nonabsorbed compounds).

Long postantibiotic effect

Should not be prescribed to children, adolescents, nursing mothers, pregnant women.

Diabetes is risk factor for several side effects

Increases warfarin levels

Question 11

Fluoroquinolones - Adverse effects

Answer 11

Nausea, vomiting, diarrhea most common

Tendonitis and tendon rupture (Increased risk in those over 60 years old, taking corticosteroids, and in those with kidney, heart, or lung transplant).

Peripheral neuropathy (Numbness, tingling, weakness, and shooting pain in the limbs, hands, and feet).

Hypo/hyperglycemia

Seizures

Photosensitivity (Phototoxicity)

QT prolongation and ventricular tachycardia

CNS stimulation by inhibition of caffeine + theophylline metabolism by cytochrome P450 1A2

Insomnia
Restlessness
Anxiety
Light-headedness
Confusion
Arthropathy

Question 12

Group 1 Fluroquinolones

Answer 12

Norfloxacin.

Least active of the fluoroquinolones against both gram-negative and gram-positive organisms, with minimum inhibitory concentrations (MICs) fourfold to eightfold higher than those of ciprofloxacin..

Question 13

Group 2 Fluoroquinolones

Answer 13

Ciprofloxacin, enoxacin, lomefloxacin, levofloxacin, ofloxacin, and pefloxacin.

Excellent gram-negative activity and moderate to good activity against gram-positive bacteria.

Gram-negative cocci and bacilli, including Enterobacter sp, P aeruginosa, Neisseria meningitidis, Haemophilus sp, and Campylobacter jejuni

Question 14

Group 3 Fluoroquinolones

Answer 14

Gatifloxacin, gemifloxacin, and moxifloxacin.

Improved activity against gram- positive organisms, particularly S pneumoniae and some staphylo- cocci.