antibacterial drugs affecting nucleic acids/biosynthesis Flashcards
what are the 2 classes of drugs that target nucleotide matabolism
sulfonamide and trimethoprim
what are sulfa drugs derived from
german dye industry
can sulfa drug prevent bacterial growth in vivo
yes but not in vitro and it is a prodrug
what type of inhibitor is sulfa drug and what is it a substrate for
competitive and for DHPS
what are trimethoprims
synthetic agent,
what are clinical applications fo sulfonamides and trimethoprim
respiratory, urinary, digestive tract infections.
what is the mode of actions for quinolones
it targets DNA gyrase and DNA topoisomerase 4
how do quinolones actively poison bacteria
they trap gyrase/topoisomerase 4 on DNA drug/enzyme/DNA complexes leading to double strand DNA breaks.
are quinolones bacteriacidal
yes
in early generations what was gyrase a primary target of
gram negative while topoisomerase 4 was a secondary target.wh
what happens to quinolone specificity in gram positive bacteria
it is reversed
what is the quinolones selectivity of action
there is no gyrase in mammalian cells
give some examples of the different generations of quinolones
1st- nalidixic acid
2nd- ciprofloxacin, norfloxacin, ofloxacin
3rd- levofloxacin
4th- moxifloxacin
what are the side effects that can occur from quinolones
gastrointestinal disturbance, CNS toxicity, phototoxicity, hypotension, tachycardia, haematological changes, drug interactions, interfere with caffeine metabolism, tendonitis, arthropathy
name the nitroimidazoles
benzimidazole, metronidazole, nimorazole, ornidazole, secnidazole, tinidazole.
what is the antibacterial spectrum of metronidazole
potent action against most obligate anaerobic bacteria. active against some facultative anaerobes under anaerobic conditions.
what is the mode of action of metronidazole
nitro group of the drug is reduced by low redox potential nitroreductases
what are some toxic effects of metronidazole
DNA damage, oxidation, strand breaks, helix destabilised
what are some clinical applications of metronizadole
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
what are some side effects of metronidazole
gatrointestinal disturbance, CNS effect, reversible neutropenia.
what are rifamycins
transcription inhibitor, natural product
what is the mode of action of rifamycin
binds the beta subunit of prokaryotic RNAP and interferes with initiation of transcription. it is also bactericidal.
what does rifamycin treat when in combination
TB, leprosy, penicillin-resistant s.pneumoniae, s.aereus
what are some formulations of rifamycin
rifapentine-oral,
rifaximin-oral/topical,
rifamycin-im/iv/topical,
rifampin-oral/iv
what are some side effects of rifamycin
non toxic, following can happen, hepatitis, skin reactions, febrile reaction, immunosuppressive effects
