Exam One Antibiotics: MOA, AE, USE etc Flashcards
• Therapeutic Use: Bactericidal Antibiotic
• MOA: cell wall synthesis inhibitor by inhibiting transpeptidase
• AE: inactivated by B-lactamases, mutant transpeptidases, down-regulated porins, efflux pump.
• Drug interactions: Not metabolized, excreted by kidney. Do not enter CNS, unless inflammation present.
• Notes: Probenecid decreases excretion of penicillins. Anti-staph penicillins are Isoxazolyls (Dicloxacillin and Oxacillin). Nafcillin and Dicloxicillin are penicillinase resistant penicillins.
o TAAM: Broad spectrum
o DOPP: Narrow spectrum
Cell Wall Synthesis Inhibitors
Penicillins
Penicillin G Penicillin V Oxacillin Dicloxacillin Ampicillin Amoxicillin Ticarcillin Mezlocillin
- Therapeutic Use: Nosocomial pneumonia, cellulitis, sinusitis, bone & joint infections.
- MOA: bind irreversibly to and inhibit bacterial -lactamases.
- AE: Cross the BBB
- Drug interactions: Widely distributed, even to brain; renally excreted.
- Notes: Not bacteriostatic or bactericidal (NOT ANTIBIOTICS). Piperacillin increases half-life of tazobactam.
ß-Lactamase Inhibitors
Clavulanate (oral)
Sulbactam (IV)
Tazobactam (IV)
• Therapeutic Use: Broad spectrum bactericidal (especially nosocomial pneumonia: pseudomonas aeruginosa, MRSA, Gr-‘s).
• Active: Gr+ cocci, Gr- with G2, G3, G4. Not MRSA or enterococci.
• MOA: Inhibit Cell wall synthesis by blocking transpeptidase.
• AE: if Pt is allergic to penicillin, probably allergic to cephalosporins. GI stress,
• superinfections, increases bleeding, Disulfram-like toxic Reaction w/ alcohol (red-face).
• Resistance: inactivated by -lactamases, mutation, porin down-regulation, efflux pumps
• Drug interactions: Unmetabolized and excreted by kidney.
• Notes: G4s are generally better than penicillins EXCEPT for anaerobes.
o Anti-pseudomonals treated with a G3 or G4 with clindamycin, cipro, imipenem, or meropenem.
o Probenecid (uricosuric agent) decreases excretion of cephalosporins.
o 1st Gen cephalosporin is a good empiric choice (Dr. Latva).
o OMNICEF po is a 3rd gen cephalosporin for ped puncture wound.
o Extra C makes them more resilient to Beta lactamases.
Cephalosporins (Beta-lactam antibiotics)
1st Generation
Cefazolin
Cephalexin
2nd Generation
Cefuroxime
Cefoxitin
3rd Generation Cefixime Cefoperazone Cefotaxime Ceftriaxone
4th Generation
Cefepime
Cefpirome
- Therapeutic Use: Serious Broad-spectrum infections; Cilastin increases imipenem’s t1/2. Anti-pseudomonal.
- MOA: Inhibit cell wall synthesis by inhibiting transpeptidase preventing PG crosslinking. Excreted by kidneys.
- AE: distributes to brain; poor oral absorption. Penicillin allergic pt will have 50% allergy to carbapenems. GI distress
- Drug interactions: some strains of Pseudomonas are resistant.
- Notes: Not effective against MRSA, enterococcus, C. dificile, Legionella.
- Cilastatin inhibits dehydropeptidase preventing imipenem’s degradation by kidney.
Carbapenems
Imipenem/Cilastatin
- Therapeutic Use: Gr- & anaerobes; Serious narrow-spectrum infections, bactericidal and anti-pseudomonal.
- MOA: Inhibit cell wall synthesis by inhibiting transpeptidase preventing PG crosslinking.
- AE: GI distress.
- Drug interactions:
- Notes: Not effective against MRSA, enterococcus, C. dificile, Legionella. if pt is allergic to penicillin and carbapenem this is good to give.
Monobactams
Aztreonam
- Therapeutic Use: IV, Non-beta-lactam cell wall inhibitor. MRSA!!!
- MOA: binds D-ala D-ala moiety of pentapeptide of outer membrane preventing transpeptidase.
- AE: poor oral absorption, wide distribution (not to brain), excreted unchanged by kidney. Thrombophlebitis, red man syndrome; Ototoxicity and nephrotoxicity (if combined with aminoglycoside).
- Resistance: enterococci
- Notes: for serious infections by Gr-, especially MRSA. Drug of last resort. VancoR enterococci get synercid (quinupristin / dalfopristin) or linezolid.
Vancomycin
- Therapeutic Use: Topical, Non-beta-lactam cell wall inhibitor. Gr+.
- MOA: inhibits de-P of C55 isoprenyl pyrophosphate carrier. Blocks addition of UDP from getting to membrane.
- AE: wide distribution, kidney excreted. Severe nephrotoxicity so only used topically!
- Resistance: None
- Notes:
Bacitracin
- Therapeutic Use: Narrow Spectrum (MRSA, vanco resistant Enterococcus, strep.)
- MOA: Streptogramin; Protein synthesis inhibitor by binding 23S RNA of 50S subunit. Inhibits peptidyl transferase blocking elongation.
- AE: thrombophlebitis, athralgia, myalgia. Poor oral absorption.
- Resistance: lil known
- Drug interactions: Increases effects of warfarin, diazepam, NNRTIs, and cyclosporines.
- Notes: used in combination as Synercid. Dalfo is early phase and Quinu is late phase. Bacteriostatic, -cidal when used with lenezolid. Metabolized in liver and excreted in feces.
Protein Synthesis Inhibitors
Streptogramins
Quinupristin/dalfopristin
- Therapeutic Use: VRE, MRSA, penicillin res Strep. Anti-TB
- MOA: Oxazolidinone, protein synthesis inhibitor. Binds 23S RNA of 50S subunit inhibiting formation and initiation. Good oral absorption or IV
- AE: Not good against Gr-. GI distress.
- Drug Interactions: augments action of antidepressants and serotonin.
- Resistance: some enterococcal strains.
- Notes: bactericidal when used with Synercid.
Oxazolidinones Linezolid (Zyvox)
- Therapeutic Use: Bacteriostatic, but –cidal at high doses. Chlamydia, mycoplasma, mycobacterium, Legionnaire’s, MAC
- MOA: Bind 50S subunit and block formation of translation complex
- AE: GI distress, Cholestatic hepatitis (failure of bile flow).
- Resistance:
- Notes: Good for pt allergic to penicillin. Lots of other drug interactions. Erythromycin used for topical acne treatment.
Macrolides ACE
Azithromycin
Clarithromycin
Erythromycin
- Therapeutic Use: Ketolide (semi-synthetic macrolide), respiratory tract infection where macrolides don’t work.
- MOA: Inhibits CYP3A4 system.
- AE:
- Resistance:
- Notes: Taken orally. Back-up to macrolides.
Ketolides
Telithromycin
- Therapeutic Use: Lincosamide; penicillin res. Gr+, anaerobes, Chlamydia, strep, staph, pneumococci.
- MOA: binds 23S RNA of 50S inhibiting translation and formation of initiation complex.
- AE: GI distress, respiratory paralysis (baclofen, diazepam, atracurium)
- Resistance: Not for Gr-. Do not give with a muscle relaxant!!!
- Notes: Bacteriostatic, good for pt allergic to penicillin. For nosocomial pneumonia use with G3 or G4 cephalosporin. Used for acne treatment.
Lincosamides
Clindamycin
- Therapeutic Use: Gr-, Gr+, Pseudomonas, endocarditis, septicemia, nosocomial pneumonia, UTI. Anti-TB
- MOA: Bind 16S RNA subunit of 30S ribosomal subunit and inhibits protein synthesis.
- AE: Ototoxicity, Nephrotoxicity (w/ vanco or cyclosporine), NM blockade, respiratory distress.
- Resistance: Anaerobes
- Notes: Bactericidal. Poor oral absorption. Unmetabolized and eliminated by kidneys.
- SGT-KA
Aminoglycosides
Streptomycin Gentamicin Tobramycin Kanamycin Amikacin
- Therapeutic Use: Gr+, Gr-, anaerobes, Chlamydia, mycoplasmas, protozoa.
- MOA: Bind 16S to the 30S ribosomal subunit and block docking of tRNA on ribosome.
- AE:
- Resistance:
- Notes: Bacteriostatic. Use DOXYCYCLINE unless otherwise noted.
Tetracyclines
Tetracycline
Doxycycline
Minocycline
- Therapeutic Use: New IV broad spectrum Abx against many drug resistant organisms (MRSA) for skin infections.
- MOA: Glycycycline. Bind 16S to the 30S ribosomal subunit and block docking of tRNA on ribosome. Metabolized in liver, excreted by kidneys
- AE: Incorporates into teeth and bones, phototoxicity, GI distress, oto-, hepato-, nephrotoxicity. Superinfections.
- Resistance: Pseudomonas
- Notes: Tetracycline derivative, don’t give to kids (goes into teeth!), pregnant, renal/liver implant.
Glycycyclines
Tigecycline (Tiger striped teeth)