Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Pharmacology (Fall) > Antibiotics III: Protein Synthesis Inhibitors > Flashcards

Antibiotics III: Protein Synthesis Inhibitors Flashcards

1
Q

How do Protein Synthesis Inhibitors work?

A

work by binding to ribosome & interfering with protein synthesis

mammalian cells have 80S ribosome (60S & 40S subunits)

bacteria have 70S ribosome (50S & 30S subunits)

diff. therefore we can target the 50S for ex & it won’t affect our cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What do the Protein Synthesis Inhibitors include?

A
  • Macrolides
  • Tetracyclines
  • Aminoglycosides
  • Lincomycin
  • Oxazolidinones
  • Streptogramins & Chloramphenicol
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is the process of Protein Synthesis?

A

ADD!

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are examples of Macrolides?

A
  • Erythromycin, Azithromycin – IV or PO
  • Clarithromycin – PO (CYP3A4 Inhibitor & substrate)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is the target of Macrolides?

A
  • Azithromycin – prolongs QT, CYP3A4 substrate, very long half life ~ 70 hours (*benefit b/c can dose it for 3 days at a high dose instead of needing it for a week – t1/2 allows it to stick around for a while)
  • Ezithromycin – CYP3A4 substrate & inhibitor
  • Binds to 50S subunit & prevents translocation (movement of ribosome along mRNA)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are the features of Macrolides?

A
  • Bacteriostatic, time dependent
  • Distribution – extensive into tissue, poor CSF penetration
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is the Spectrum of Activity for Macrolides?

A
  • Variable gram + (good listeria), some gram -, some anaerobes, good atypical coverage
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are examples of Tetracyclines?

A
  • Tetracycline, doxycycline, minocycline – PO
  • Doxycycline – 1st line for lime disease (after a tick bite & for treatment)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is the target of Tetracyclines?

A
  • Binds to the 30S subunit & interferes with the attachment of tRNA to mRNA-ribosome complex
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are the features of Tetracyclines?

A
  • Bacteriostatic, time dependent
  • Divalent cations (Ca2+, Mg2+) bind to tetracyclines in gut & prevent absorption (avoid milk or Ca2+, Mg2+ supplements)
  • Doxycycline does NOT have to be adjusted in renal impairment
  • Good tissue & body fluid distribution but NOT CSF
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is the Spectrum of Activity for Tetracyclines?

A
  • Variable gram + (sometimes will cover MRSA, covers listeria), moderation gram -, some anaerobes, good atypical coverage
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are examples of Aminoglycosides?

A
  • Gentamicin, tobramycin, amikacin – IV/IM, topical (in eye & ear drops, ~ IV in hospital)
  • Great drugs; v. effective, but v. toxic
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is the target of Aminoglycosides?

A
  • Binds to 30S ribosomal subunit & causes mRNA to be incorrectly read
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What are the features of Aminoglycosides?

A
  • Concentration dependent killing (more imp. Is how highly that peak is above the MIC)
  • Bacteriocidal
  • Post-antibiotic effect – allows for high dose once daily administration (even when antibiotic is away, it still inhibits the regrowth of a bacterium for a period of time)
  • Adjust dose for renal impairment
  • distribution - mostly into ECF, low tissue concentrations, poor CSF penetration (therefore don’t cross BBB v. well)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the Spectrum of Activity for Aminoglycosides?

A

NARROW
* Aerobic gram – coverage incl. pseudomonas aeruginosa

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are the adverse effects of Aminoglycosides?

A
  • NEPHROTOXICITY – taken up by the cells in the proximal tubule &  can cause an acute tubular necrosis
    o Risk factors incl: large total dose, prolonged duration of therapy, high trough concentrations, CKD, elderly, dehydration
  • NEUROTOXICITY – may cause issues with hearing & balance-usually irreversible
  • OTHER – numbness, twitching, tingling skin, convulsions (monitor & ask about this)
17
Q

What is the monitoring for Aminoglycosides?

A
  • Drug levels, usually trough levels (initially weight based dosing – Ideal Body Weight) – want to see v. minimal levels of aminoglycosides after 24 hrs
18
Q

What are examples of Lincomycin?

A
  • Clindamycin – IV or PO
19
Q

What is the target of Lincomycin?

A
  • Reversibly binds to the 50S subunit & prevents peptide bond formation (prevents peptide being added & the chain becoming longer)
20
Q

What are the features of Lincomycin?

A
  • Bacteriostatic
  • Hepatic clearance
  • Distribution: Tissues & body fluids, NOT CSF
21
Q

What is the Spectrum of Activity for Lincomycin?

A
  • Good gram + coverage (incl. MRSA), no gram – coverage, good anaerobic coverage but NOT clostridium difficile
  • therefore good gram + & anaerobic but rest not (no gram -)
22
Q

What are the adverse effects of Lincomycin?

A
  • c. difficile associated colitis (severe diarrhea that can be fatal), esophagitis
23
Q

What are examples of Oxazolidinones?

A
  • Linezolid IV or PO
24
Q

What is the target of Oxazolidinones?

A
  • Binds to the 23S ribosomal RNA of the 50S subunit
  • It prevents the formation of the initiation complex that is required for translation (prevents everything from really starting)
25
Q

What are the features of Oxazolidinones?

A
  • Bacteriostatic (enterococcus & staph)
  • Bacteriocidal (strep)
  • Time dependent
  • Dose not adjusted in renal impairment
26
Q

What is the Spectrum of Activity for Oxazolidinones?

A
  • Gram + incl. MRSA & vancomycin resistant enterococci (VRE)
27
Q

What are the adverse effects of Oxazolidinones?

A
  • Hematologic (BIG CONCERN) & neurotoxicity (generally avoid treatment duration longer than 2 weeks – b/c almost everyone gets hematological toxicity)
  • Distribution – good tissue penetration, CSF penetration
28
Q

What are examples of Streptogramins & Chloramphenicol?

A
  • Streptogramins – quinupristin/dalfopristin
  • Chloramphenicol
29
Q

What is the target of Streptogramins & Chloramphenicol?

A
  • Streptogramins – quinupristin/dalfopristin
    o *individually bacteriostatic, combo is bacteriocidal
    o Bind to diff. sites of the 50S subunit (dalfopristin inhibits peptidyl transfer as well as increases quinupristin binding; quinupristin prevents chain elongation)
  • Chloramphenicol
    o Binds to 50S subunit & inhibits formation of peptid bond
    o Rare use due to SE’s: gray baby syndrome (swollen stomach, low BP), & hematologic toxicity – don’t use it unless you absolutely have to)
30
Q

What are the Resistance Mechanisms?

A
  • Porin mutations – decrease entry into gram – bacteria (b/c porins will change)
  • Efflux pumps – increased removal
  • Altered targets or increased # of targets (ex: PBPs)
  • Antibiotic degradation
    o Ex’s: break open the beta lactam ring through hydrolysis rendering the antibiotic inactive (4 mem. Ring that’s under a lot of stress)
     Penicillinases
     Extended spectrum betalactamases (ESBLs)
     Carbapenemases

Pharmacology (Fall) (28 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions