Inhibitors of DNA/RNA synthesis

Question 1

Fluoroquinolones

Answer 1

Drugs: “–floxacin”

Bacteriocidal

Inhibit one of two enzymes:
DNA gyrase
Topoisomerase IV

Impaired absorption with food or cations
Distributes evenly to body except CNS

Question 2

Daptomycin

Answer 2

A lipopeptide
UNIQUE MOA:
Binds bacterial membrane –> depolarizes cell
Loss of membrane potential halts RNA, DNA< and protein synthesis –> cell death

NO cross resistance with other drugs observed

Excreted unchanged in urine

Question 3

3 Drugs with distinct mechanisms

Answer 3

Metronidazole
Nitazoxanide
Tinidazole

All 3 may be mutagenic or carcinogenic

Question 4

Riflaximin

Answer 4

Inhibits RNA synthesis by binding RNA polymerase (also Rifampin–anti-mycobacterial)

NOT absorbed in GI tract
– excreted unchanged in feces
NOT interfere with CYP enzymes–vs. Rifampin! major drug-drug intxn concerns