Inhibitors of Nucleic Acid Function

Question 1

How does gene transcription differ in prokaryotes from eukaryotes?

Answer 1

Transcription and translation are coupled. mRNA transcription begins while the mRNA is still forming.

Question 2

What is DNA Gyrase?

Answer 2

Topoisomerase II- relaxes supercoiled bacterial chromosomes

Question 3

What does RNA Primase do?

Answer 3

Acts as a polymerase for the lagging strand forming okazaki fragments

Question 4

What does DNA polymerase II do?

Answer 4

Removes RNA primers from RNA Primase and replaces with DNA nucleotides

Question 5

What does Topoisomerase IV do?

Answer 5

Separates the daughter chromosomes during cell division.

Question 6

What targets Topoisomerase II &4

Answer 6

Quinolones and Fluoroquinolones

Question 7

What targets DNA polymerase II

Answer 7

Rifampin

Question 8

What fluoroquinolone can pass the Blood brain barrier

Answer 8

Oxfloxacin

Question 9

What is the spectrum of Quinolones?

Answer 9

1st gen- Gram -

Newer- Gram - and Topo IV gives gram +

Question 10

Why does targeting Topoisomerases effective and why does it not affect the host

Answer 10

Structural differences between humans and bacteria allow the targeting to only affect bacteria.

Question 11

What is the 2nd generation fluoroquinone and what is its spectrum?

Answer 11

Ciprofloxacin

gram -, and gram + rods, intracellular atypical

Question 12

What is the best fluoroqunione for Pseudomonas?

Answer 12

Ciprofloxacin

Question 13

What to use to treat anthrax

Answer 13

Ciprofloxacin

Question 14

What is the most common 3rd generation Fluoroquininone and what is its spectrum

Answer 14

Levoflaxacin

gram -, and improved atypical and Gram + activity

Question 15

When is Levoflaxacin used?

Answer 15

In conjunction with other antimicrobials

Question 16

What is the 4th generation Fluorquinone and what is its spectrum

Answer 16

Moxifloxacin- gram -/+ and anaerobes

Question 17

What needs to be avoided with Fluoroquinones?

Answer 17

Al+, Mg+ and other divalents

Question 18

Side effects of of Fluoroquinones

Answer 18

GI upset, headache, dizziness, photosensitivity, seizures (other underlying problems- epilepsy, use of theophylline inhaler for asthma, and use of NSAIDs), Disulfuram-Like effect

Question 19

What causes C. difficile superinfection most often?

Answer 19

Ciprofloxacin

Question 20

What are the rare risks of fluoroquinones?

Answer 20

Increased QT interval, worsens Myesthenia Gravis, Risk of rupturing tendons, possibly teratogen.

Question 21

What drug inhibits DNA replication in anaerobic cells

Answer 21

Metronidazole

Question 22

What is the drug of choice for Tetanus and C Difficile superinfection

Answer 22

Metronidazole

Question 23

What is the side affect of Metronidazole

Answer 23

Disulfiram-Like interaction, dark urine, metallic tase and GI disturbance

Question 24

What drug inhibits RNA Primase and what is its spectrum

Answer 24

Rifampin- Gram +/- and Mycobacteria

Question 25

What are the side effects of Rifampin

Answer 25

Orange/Red bodily fluids, GI upset, Hepatoxicity, CYP450 inducer

Question 26

What drug creates highly-reactive intermediates?

Answer 26

Nitrofurantoin- bactericidal

Question 27

Side effects of Nitrofurantoin

Answer 27

Hepatotoxicty, neuropathy, pulmonary fibrosis, and drug-induced lupus

Question 28

When should Nitrofurantoin not be used

Answer 28

Last 4 weeks of pregnancy or in neonates up to 1 month-hemolytic anemia
Patients with decreased renal function

Question 29

Why use Nitrofurantoin for UTI?

Answer 29

90% absorbed into urine and 40% excreted in urine unchanged within 45 min so it stays in the bladder and is effective for treating susceptible UTIs.