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IOS 10 Exam 2
Tetracyclines & Glycyclines
Question | Answer |
---|---|
MOA of tetracycline | Bacteriostatic- Bind 30S ribsosomal subunit to aminoacyl transfer RNA to inhibit elongation |
MOA of glycycline | Bind 30S subunit of ribosome and inhibit elongation |
Resistance of tetracycline- | Considered constitutive, but can be plasmid mediated- penetration of porin, or efflux proteins |
Resistance of glycylcylines | Ribosomal modification and active drug efflux |
Gram + aerobe activity of Tetracycline | Intrinsic activity, strep, staph, MRSA, VRE (minocycline best against MRSA) |
Gram -aerobe activity of tetracycline | Active but limited by PK |
Anaerobic activity of tetracyclines | Active but limited by resistance |
Atypical activity of tetracyclines | Good activity especially chlamydia |
Other activity of tetracyclines | H.pylori, rickettsial (rocky mountain spotted, lyme dx) |
Tetracycline ADME | Good oral bio,ALTERED BY FOOD, AL< MG, CA, Dairy, HUGE VD, all tissue less CNS penetration, no metabnolism, and up to 70 renal |
Tetracycline SE | Deposition in teeth and bone, hepatotoxic (pregnant), GI discomfort, CNS, Superinfection with Candida, and resistant stap, Thrombophlebitis, phototoxcity with demeclocycline |
Tetracycline DI | Drugs containing di and tri-valent cations(2-3 hours before or 2 after), warfarin, OC |
Gram + activity of Glycycline | Highly active against MRSA, S epi, most strep, enterococci (and VRE) |
Gram - aerobes activity of glycyclines | Excellent activity Enterobacteriae, citobacter, acinobacter, strenotrophomonas, poor pseudomonas activity |
Anaerobes activity of glycyclines | Excellent-Bacteroides fragilis, Bacteroides group, Fusobaterum, Clostridium, Peptostreptococcus |
Glycycycline ADME | Poor absorption, HUGE VD t 1/2 42 hrs, Elimination- 40% renal 60% fecal |