Part 7 Flashcards
B lactam antibiotics mechanism of action
Disrupt bacterial cell wall causing them to take up water and burst through inhibiting transpeptidases that catalyze cell wall formation and activation of autolysins that cleave bonds in wall by binding Penicillin binding proteins
B-lactamases definition
Coded for by a plasmid between bacteria to promote synthesis of proteins that release into the space around them to cleave certain PCNs
PCN drug interactions (3 to know)
1) probenecid - delay excretion
2) aminoglycosides - inhibed by PCNs and need to be administered separately
3) Bacteriostatic antibiotics - PCNs work best on fast dividing
Anti pseudomonal penicillin name
-Piperacillin
1st -5th gen cephalosporins trend (3)
- 1st gen most susceptible to B lactamases, 5th is highly resistant
- Increased activity against gram - bacteria
- increased ability to reach csf
List example 1st-5th gen cephalosporins
1) cephalexin (keflex)
2) Cefaloxin
3) ceftazidime, cefdinir (omnicef), or ceftriaxone (roecephin)
4) cefipime
5) ceftaroline (effective gainst MRSA)
Disulfiram like reaction can occur with metronidazole. What other drug class can it possibly occur with?
Cephalosporins (apparently)
Carbapenems drug class and MOA
B-lactam antibiotis that like penicillins and cephalosporins, inhibit bacterial cell wall synthesis, have very broad antimicrobial spectrum
Vancomycin adverse effects (3)
- Renal failure (dose related)
- Ototoxicity
- Red man syndrome (histamine release resulting in rashes, flushing, potential to go into shock)
These two antibiotic classes should never share an IV bag
PCNs and aminoglycosides
What is the broadest spectrum aminoglycoside
Amikacin
Tetracyclines mechanism of action
Broad spectrum antibiotics that inhibit protein synthesis at the ribosome 30s subunit after being transported via energy dependent processes
Tetracycline absorption
Via GI, but form insoluble chelates with cations preventing absorption and thus require administration 1-2 hours after ingestion of a chelate
Tetracycline common side effects (3)
- GI upset
- bones and teeth coloraion
- photosensitivity
Macrolides mechanism of action
Broad spectrum antibiotics that act by inhibiting bacterial protein synthesis, bind 50S ribosome and are bacteriostatic
Macrolide common adverse effects (2)
-GI effects
-QT prolongcatoin which can precipitate torsades de pointes
Chloramphenicol MOA and why is it not commonly used? What is it drug of choice for? What is another condition this is linked to?
Similar to a macrolide, not commonly used because has adverse effect of aplastic anemia requiring close monitoring, is still sometimes used as drug of choice in eye infections and typhoid or meningitis. In pediatrics, this is linked to gray baby syndrome which is where it builds up to toxic levels causing abdominal distension, gray coloration of skin, possibly shock and death
Fluorquinolones mechanism of action
Passive diffusion, inhibit DNA replication on bacterial gyrase and toposioromase, rapidly bactericidal
3 common B-lactamase inhibitors to be combined with penicillinase sensitive PCN
1) clavulanic acid
2) tazobactam
3) sulbactam
IV calcium gluconate with ceftriaxone injection
contraindicated due to calcium precipitate formation
Teicoplanin
Similar action and structure to vancomycin, but largely devoid of any ADRs
Fosfomycin
Similar action and structure to vancomyscin, often used in uncomplicated UTI
Telavancin
Similar action and structure to vancomycin, treats complex skin infections and causes taste disturbance and foamy urine
4 tetracyclines available
1) tetracycline (short acting, no food)
2) denecocycline (medium acting, no food)
3) doxyxcline(long acting, no food)
4) minocycline (long acting, food okay)