L33- Misc. Antibiotics Flashcards
Metronidazole:
- posses (1) activity in addition to antibacterial, include all
- effective against (2) bacteria
- bacteri-(ostatic/cidal)
1- antimicrobial, amebicide, antiprotozoal
2- anaerobic bacteria
3- bactericidal
Metronidazole MOA:
- requires (1) conditions
- (2) occurs initially upon entry, resulting in (3) in order to cause (4)
1- anaerobic conditions (optimal activity, see (2))
2- reductive bioactivation of Nitro group by Ferredoxin
3- forms cytotoxic products
4- interfere with nucleic acid synthesis –> damages DNA
Metronidazole Pharmacokinetics:
- (1) route of administration
- (2) describe distribution
- (3) route of elimination
1- oral, IV, rectal, topical
2- well distributed, including CSF
3- hepatic metabolism
Metronidazole AEs:
- (1) are the hallmark AEs
- (2) is the dangerous AE when combined with certain substance
- (3) are seen with prolonged use
- (4) are rare AEs
- (5) may develop post-therapy
- (6) contraindications
1- HA, dark urine, metallic taste
2- disulfiram like rxn w/ EtOH
3- GI irritation, stomatis, peripheral neuropathy
4- leukopenia, dizziness, ataxia
5- opportunistic fungal infections
6- 1st trimester, not advised
Rifampin binds (1) subunit on (2) in order to prevent (3)
1- β-subunit
2- DNA-dependent RNA polymerase
3- inhibits RNA synthesis and protein synthesis
describe mechanisms of Rifampin resistance
- point mutations in rpoB gene for β subunit of DNA sep. RNA poly. —> dec drug affinity for its target site
- decreased permeability
Rifampin uses:
- drug of choice for (1)
- prophylaxis for (2) and (3)
- alternative for (4)
1- Tb in combination
2- meningitis exposure
3- H. influenzae (type B) exposure in children
4- MRSA w/ vancomycin
Rifampin Pharmacokinetics:
- (1) route of administration
- (2) describe distribution
- (3) route of elimination
- (4) hepatic effect
1- oral, parenteral
2- well-distributed, including CSF
3- feces
4- CYP450 inducer
Rifampin AEs:
- (1) common harmless effect
- (2) other common AEs
- (3) occasional AEs
- (4) discuss use in pregnancy
Well-tolerated, used for months in Tb Pts
CYP450 inducer —> drug interactions
1- harmless red/orange color of bodily fluids
2- GI distress, light chain proteinuria
3- thromboytopenia, rashes, nephritis, liver dysfunction
4- safe
Polymyxin B:
- (1), simple structure
- active against (2) bacteria as (3) are resistant
- bacteri-(ostatic/cidial)
1- peptide
2- Gram- bacteria (active)
3- Gram+ bacteria (inactive)
4- bactericidal
Polymyxin B MOA:
- similar action to (1) agents
- binds and disrupts (2) as main action
- also binds and inactivates (3)
1- cationic detergents
2- bacterial cell membranes
3- endotoxin
Polymyxin B:
- (1) main clinical use
- (2) are alternative / emerging uses
1- Topical for superficial skin infections
2- Parenteral for resistant spp.: actinetobacter baumannii, P. aeruginosa, enterobacteriaceae
list Polymyxin B AEs
Topically- very few
Parenterally- extremely nephrotoxic (benefits must outweigh risks for parenteral use)
(1) is one of the main Urinary Antiseptics, which are limited to (2). (1) has bacteri-(ostatic/cidal) against (4) bacteria. Note- (5) is the main cause of (2) infections.
1- Nitrofurantoin
2- UTI prophylaxis and Tx
3- both
4- Gram+ and Gram- bacteria
5- E. Coli
Nitrofurantoin undergoes (1) by bacteria in the urine, leading to (2) formation that have (3) actions.
-(4) discuss resistance
1- reduction rxns
2- reactive intermediates
3- damage bacterial DNA
4- slow emergence, no cross-resistance
