Inhibitors of nucleic acid synthesis

Question 1

Name the Rifamycins.

Answer 1

rifabutin, rifampin, rifapentine

Question 2

What is the activity of rifamycines?

Answer 2

CIDAL 50s Intermediate

Question 3

What are rifamycins indicated for?

Answer 3

mycobacterial infection

Question 4

What is the MoA of rifamycins?

Answer 4

inhibition of bacterial DNA-dependent RNA polymerase - inhibits RNA synthesis and therefore nucleic acid synthesis

Question 5

Describe the toxicity of rifamycins

Answer 5

hepatotoxicity, discoloration of bodily fluids (highly conjugated and discolored)

Question 6

What do rifamycins induce?

Answer 6

cyto P450 in the liver - leads to decrease in serum concentration of metabolized drugs; rifabutin is least potent inducer

Question 7

What is the MoA of quinolones in gram - bacteria?

Answer 7

inhibition of DNA gyrase - therefore inhibition of replication and transcription

Question 8

What is the MoA of quinolones in gram + bacteria?

Answer 8

inhibition of topoisomerase IV - this inhibits the separation of daughter DNA as a product of DNA replication

Question 9

What are the first generation quinolones?

Answer 9

nalidixic acid and cinoxacin

Question 10

Quinilones bind to what

Answer 10

polyvalent cations - can’t take iron supplements or dairy, etc

Question 11

What are the side effects of quinolones?

Answer 11

tendon rupture, phototoxicity, peripheral neuropathy, prolongation of QT interval, inhibitors of P450 enzymes, severe liver injury (trovafloxacin)