Antibiotics: Nucleic acid inhibitors

Question 1

what are nucleic acid inhibitors?

Answer 1

they are inhibitors of folic acid

they are direct inhibitors of nucleic acid synthesis

Question 2

what are the 2 categories of nucleic acid inhibitors?

Answer 2

1. Inhibitors of folic acid synthesis
2. Direct inhibitors of nucleic acid synthesis

Question 3

what 2 enzymes are used by bacteria in order to make its DNA strands?

Answer 3

DNA topoisomerase II (gyrase)

DNA topoisomerase IV

Question 4

what vitamin is essential for bacteria to synthetize nucleic acid?

Answer 4

TH4

(tetrahydrofolic acid)

Question 5

do bacteria synthesize their own folate?

Answer 5

yes

Question 6

what is the active form of folate made by bacteria?

Answer 6

TH4

Question 7

what enzyme do bacteria need to make their own folate?

Answer 7

dyhydrofolate reductase to make dihydrofolate - the precursor of folate

Question 8

what do you use to inhibit dihydrofolate reductase?

what will this cause?

Answer 8

folate antagonist or trimetroprim

prevents conversion of dihydrofolate to tetrahydrofolate

Question 9

what is an example of a folic acid inhibitor?

Answer 9

sulfonamides

Question 10

how do sulfonamides work?

Answer 10

compete with PABA, therefore inhibiting folate synthesis

Question 11

what are 2 examples of sulfonamides?

Answer 11

sulfamethaxazole

silver sulfadiazine

Question 12

when are sulfonamides administered?

Answer 12

mild urinary tract infections

conjunctivitis

burns

Question 13

what are sulfonamides known as?

Answer 13

antimetabolites

Question 14

what adverse reactions can sulfonamides cause?

Answer 14

• hypersensitivity = steven johnson syndrome (peeling skin/blisters, fever, respiratory problems)
• nephrotoxicity = crystal formation (white urine)
• hemolysis: glucose 6 phosphate dehydrogenase deficiency
• kernicterus = displacement of bilirubin

Question 15

what is cotrimoxazole used to treat?

Answer 15

PCP (pneumocystis jirovecii)

urinary tract infection

Question 16

what is cotrimoxazole ?

Answer 16

combination of sulfamethoxazole (SXT) & trimethoprim (TMP)

Question 17

sulfamethoxazole (SXT) & trimethoprim (TMP) in combination will act as bacteriostatic or bacteriocidal?

Answer 17

they will act as bacteriocidal

Question 18

what are Fluoroquinolones?

Answer 18

drugs that inhibit bacterial enzymes needed for DNA replication

Question 19

what enzymes do Fluoroquinolones target?

Answer 19

DNA topoisomerase II (DNA gyrase)

DNA topoisomerase IV

Question 20

how many groups do Fluoroquinolones have?

Answer 20

3

Question 21

what is norfloxacin used for?

what other drug can be used?

Answer 21

urinary tract infection

cipro

Question 22

what is the 1st group of fluoroquinolones?

Answer 22

norfloxacin

Question 23

what is the 2nd group of fluoroquinolones?

Answer 23

Ciprofloxacin**, Ofloxacin

Question 24

what is the 3rd group of fluoroquinolones?

Answer 24

Sparfloxacin

Question 25

2nd group fluoroquinolones is used against what bacteria?

Answer 25

gram -

Question 26

3rd group fluoroquinolones is used against what bacteria?

Answer 26

gram - and +

Question 27

what drug is used to treat Typhoid fever?

Answer 27

ciproflaxin

Question 28

what drug is used to treat Uncomplicated Urinary tract infection?

Answer 28

cotrimoxazole

Question 29

what drug is used to treat complicated Urinary tract infection?

Answer 29

Ciprofloxacin

Question 30

what is complicated UTI?

Answer 30

when infection reaches kidneys

Question 31

what is uncomplicated UTI?

Answer 31

when infection is in the urethra

Question 32

what adverse effects can occur while taking fluoroquinones?

Answer 32

They deposit in cartilage and cause ruptured tendons\*

Question 33

fluoroquinones should not be given to whom?

Answer 33

pregnant women and children

Question 34

what type of bacteria does Metronidazole (Flagyl)\*\* target? is it bacteriostatic or bacteriocidal?

Answer 34

anaerobic bacteria and some parasites bacteriocidal

Question 35

how does metronidazole work?

Answer 35

Forms free radical toxic metabolites in bacterial cell

Question 36

what is an adverse reaction to metronidazole?

Answer 36

disulfiram like reaction (vomiting, nausea, tachycardia)

Question 37

Sulfonamides will inhibit what bacterial enzyme needed for folate synthesis?

Answer 37

Dihydropteroate syhthase