Pharm II Test 1 Flashcards
Which antibiotics are not eliminated by non-renal mechanisms?
Think D-CRIMES
Doxycycline
Clindamycin
Rifampin –> inducer of P450 (hepatotox)
Isoniazid –> genetic polymorph (hepatotox)
Metronidazole –>interacts c etoh
Erythromycin-like (macrolides) - inhibits P450
Sulfonamides - risk of renal crystalluria
Selective toxicity: inhibit pathway found in bacteria but not in humans
Folate metabolism
Selective Toxicity: Pathway exists in both, difference in enzyme structure.
- protein synthesis –> bact have 30s and 50s units
- Nucleic acid synthesis - DNA gyrase vs topoisomerase (humans)
Selective Toxicity: Macromolecular structure does not exist in humans.
Cell wall synthesis –peptidoglycan
Selective toxicity: macromolecular structure differs between microbes and humans.
Cell membrane: Ergosterol (fungi) vs cholesterol (human)
Modes of resistance
- natural
- escape
- acquired resistance
Types of acquired resistance
- Spontaneous mutational (chromosomal) resistance
- Plasmid mediated (MDR gene)
How to minimize abx resistance?
- use only when needed
- select based on susceptibility tests
- use adequate concentration / duration
Bactericidal
- inhibit cell wall synthesis
- disrupt cell membrane function
- interfere with DNA function or synthesis
Bacteriostatic
- inhibition of protein synthesis
- inhibition of intermediary metabolic pathways
Common gram + cocci
Strep
Staph
Enterococci
common gram - cocci
Neisseria
M. catarrhalis
Common gram - Rods
E.coli
Pseudomonas aeruginosa
H. influenzae
Common gram + rods
Listeria
Anaerobes, gram + rods
Clostridium difficile
H. pylori