antibacterial drugs affecting nucleic acids/biosynthesis

Question 1

what are the 2 classes of drugs that target nucleotide matabolism

Answer 1

sulfonamide and trimethoprim

Question 2

what are sulfa drugs derived from

Answer 2

german dye industry

Question 3

can sulfa drug prevent bacterial growth in vivo

Answer 3

yes but not in vitro and it is a prodrug

Question 4

what type of inhibitor is sulfa drug and what is it a substrate for

Answer 4

competitive and for DHPS

Question 5

what are trimethoprims

Answer 5

synthetic agent,

Question 6

what are clinical applications fo sulfonamides and trimethoprim

Answer 6

respiratory, urinary, digestive tract infections.

Question 7

what is the mode of actions for quinolones

Answer 7

it targets DNA gyrase and DNA topoisomerase 4

Question 8

how do quinolones actively poison bacteria

Answer 8

they trap gyrase/topoisomerase 4 on DNA drug/enzyme/DNA complexes leading to double strand DNA breaks.

Question 9

are quinolones bacteriacidal

Answer 9

yes

Question 10

in early generations what was gyrase a primary target of

Answer 10

gram negative while topoisomerase 4 was a secondary target.wh

Question 11

what happens to quinolone specificity in gram positive bacteria

Answer 11

it is reversed

Question 12

what is the quinolones selectivity of action

Answer 12

there is no gyrase in mammalian cells

Question 13

give some examples of the different generations of quinolones

Answer 13

1st- nalidixic acid
2nd- ciprofloxacin, norfloxacin, ofloxacin
3rd- levofloxacin
4th- moxifloxacin

Question 14

what are the side effects that can occur from quinolones

Answer 14

gastrointestinal disturbance, CNS toxicity, phototoxicity, hypotension, tachycardia, haematological changes, drug interactions, interfere with caffeine metabolism, tendonitis, arthropathy

Question 15

name the nitroimidazoles

Answer 15

benzimidazole, metronidazole, nimorazole, ornidazole, secnidazole, tinidazole.

Question 16

what is the antibacterial spectrum of metronidazole

Answer 16

potent action against most obligate anaerobic bacteria. active against some facultative anaerobes under anaerobic conditions.

Question 17

what is the mode of action of metronidazole

Answer 17

nitro group of the drug is reduced by low redox potential nitroreductases

Question 18

what are some toxic effects of metronidazole

Answer 18

DNA damage, oxidation, strand breaks, helix destabilised

Question 19

what are some clinical applications of metronizadole

Answer 19

given as oral, IV, topical gel/cream
treat anearobic bacteria that causes intra-abdominal infection, pseudomembranous colitis, non-venereal genital infections, respiratory tract, meningitis and brain abscesses, osteomyelitis, oral and dental infection, gastroduodenal ulcers, protozoal infections

Question 20

what are some side effects of metronidazole

Answer 20

gatrointestinal disturbance, CNS effect, reversible neutropenia.

Question 21

what are rifamycins

Answer 21

transcription inhibitor, natural product

Question 22

what is the mode of action of rifamycin

Answer 22

binds the beta subunit of prokaryotic RNAP and interferes with initiation of transcription. it is also bactericidal.

Question 23

what does rifamycin treat when in combination

Answer 23

TB, leprosy, penicillin-resistant s.pneumoniae, s.aereus

Question 24

what are some formulations of rifamycin

Answer 24

rifapentine-oral,
rifaximin-oral/topical,
rifamycin-im/iv/topical,
rifampin-oral/iv

Question 25

what are some side effects of rifamycin

Answer 25

non toxic, following can happen, hepatitis, skin reactions, febrile reaction, immunosuppressive effects