8.6

Question 1

What is the clinical use of Mupirocin?

Answer 1

• Intranasal:
• Eradication of nasal colonization with MRSA in
adult patients and healthcare workers
• Topically:
• Treatment of impetigo or secondary infected traumatic skin lesions due to S.aureus or
S.pyogenes

Question 2

What is the MOA of Mupirocin?

Answer 2

• Binds to bacterial isoleucyl transfer-RNA synthetase

resulting in the inhibition of protein synthesis

Question 3

Which drugs affect Nucleic Acid Synthesis? (3)

Answer 3

• Fluoroquinolones
• Sulfonamides
• Trimethoprim

Question 4

What is the MOA of fluoroquinolones?

Answer 4

• Enter bacterium via porins
• Inhibit bacterial DNA replication via interference with
topoisomerase II (DNA gyrase) & IV

Question 5

What is Levofloxacin ideal for?

Answer 5

Excellent activity against

S.pneumoniae

Question 6

Fluoroquinolones have their absorption affected by what?

Answer 6

Divalent cations:

• Iron
• Zinc
• Calcium

Question 7

What are the adverse effects of Fluoroquinolones?

Answer 7

• GI distress
• CNS, rash, photosensitivity
• Connective tissue problems (avoid in pregnancy, nursing mother, under 18’s) – Black Box Warning! (Esp in ankle - can be irreversible)

• QT prolongation (moxifloxacin, gemifloxacin,
levofloxacin)

• High risk of causing superinfections (C.difficile, C
albicans, streptococci)

Question 8

What are the Sulfonamides?

Answer 8

1) Sulfamethoxazole
2) Sulfadiazine
3) Sulfasalazine

Question 9

What organisms are sulfonamides used for?

Answer 9

Bacteriostatic against gram + and gram -organisms?

Question 10

Sulfonamides compete with what in it’s MOA?

Answer 10

PABA

inhibits Folic Acid synthesis

Question 11

What are the clinical applications of Sulfonamides?

Answer 11

Infrequently used as single agents (resistance)

• Topical agents (ocular,
burn infections)
• Oral agents (simple UTI’s)
• Sulfasalazine (oral) = ulcerative colitis, enteritis, IBD

Question 12

What are the adverse effects of Sulfanomides?

Answer 12

• GI distress, fever, rashes, photosensitivity are common
• Crystalluria nephrotoxicity)
• Hypersensitivity reactions
• Hematopoietic disturbances (esp. patients with G6PD
deficiency)
• Kernicterus (in newborns and infants <2 months)

Question 13

What are some drug reactions with Sulfonamides?

Answer 13

•Warfarin, phenytoin and methotrexate can lead to

increased plasma levels

Question 14

What is the contraindication of Sulfonamide?

Answer 14

• Newborns & infants < 2 months (kernicterus) – drugs compete with bilirubin for binding sites on albumin