Abx 3 (Inhibitors of Protein Synthesis) Flashcards

1
Q

Gentamincin

A
  • Aminoglycosides
  • Highly polar cations
  • Does not cross cell membranes (not absorbed through GI)
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2
Q

Streptomycin

A
  • Aminoglycosides
  • Highly polar cations
  • Does not cross cell membranes (not absorbed through GI)
  • Main use: 2nd line drug for active TB
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3
Q

Amikacin

A
  • Aminoglycosides
  • Highly polar cations
  • Does not cross cell membranes (not absorbed through GI)
  • Least susceptible to inactivation (hospital use for resistant)
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4
Q

Neomycin

A
  • Aminoglycosides
  • Highly polar cations
  • Does not cross cell membranes (not absorbed through GI)
  • OTC combo topical with polymyxin B & Bacitracin
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5
Q

Doxycycline

A

-Tetracycline

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6
Q

Tigecycline

A

-Glycycline

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7
Q

Erythromycin

A
  • Macrolide
  • Inactivated by gastric acid
  • Eliminated by hepatic CYP3A4 (interactions with other drugs)
  • Admin orally in form of esters to improve bioavailability
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8
Q

Azithromycin

A
  • Macrolide

- Admin orally in form of esters to improve bioavailability

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9
Q

Clindamycin

A
  • Binds to 50S (blocks protein bond formation)
  • Anaerobic and G+ aerobes
  • Bacteriostatic (Bactericidal depending on dose/sensitivity)
  • Should not be used in combo with macrolides or chloramphenicol
  • Severe GAS, gas gangrene & Bacteroides fragilis
  • Topical for acne
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10
Q

Chloramphenicol

A
  • Binds to 50S
  • Bacteriostatic
  • Anaerobes, G+(MRSA) & G-
  • Widely distributed in tissue
  • Metabolized by liver
  • Used only for life-threatening situations (bacterial meningitis)
  • Adverse reactions= Gray baby, bone marrow suppression (dose related) & aplastic anemia (not dose related)
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11
Q

Linezolid

A
  • Binds to 50S (unique site on 23S rRNA)
  • Bacteriostatic
  • MDR G+, VRE & MRSA
  • Adverse reactions = reversible myelosuppression (so blood counts completed weekly)
  • Neuropathy
  • Interact with MAOIs & SSRIs (serotonin syndrome)
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12
Q

Quinupristin-Dalfopristin

A
  • Bactericidal
  • Each drug separately is bacteriostatic
  • G+
  • Serious infections caused by VRE
  • Adverse reactions = Hyperbilirubinemia & arthralgia; inhibits CYP3A4
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13
Q

Aminoglycosides

A

Gentamicin
Amikacin
Streptomycin
Neomycin

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14
Q

Aminoglycosides Mechanism of Action

A
  • Bactericidal (cell death)
  • G-
  • Activity is concentration dependent
  • Transport enhanced with cell wall inhibitors (passive diffusion through outer membrane & active through plasma membrane)
  • Binds to 30S ribosomal subunit (misreading of mRNA & blockage of translocation)
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15
Q

Aminoglycosides Therapeutic Uses

A
  • Narrow spectrum
  • Used in combo with beta lactams or vancomycin for resistant bacteremia/sepsis & G+ endocarditis
  • Use sparingly/briefly to avoid toxicity
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16
Q

Aminoglycosides Adverse Reactions

A
  • Ototoxicitiy (irreversible) through elevated trough plasma levels so admin once daily high dose
  • Tinnitus is a warning sign
  • Renal impairment & prolonged administration increases risk for ototoxicity
  • Nephrotoxicity (reversible)
  • Neuromuscular blockade with high doses –> respiratory paralysis
17
Q

Tetracyclines Mechanism of Action

A
  • Active transport system (accumulation of drug in bacterial cells since mammalian cells lack these transport systems)
  • Binds to 30S ribosomal subunit (inhibits addition of AA)
  • Bacteriostatic
18
Q

Resistance to Tetracyclines

A
  • Increased drug efflux & production of proteins that interfere with drug binding to 30S
  • Glycyl chain of Tigecycline = resistant to efflux & increases 30S binding affinity
19
Q

Tetracyclines Pharmacokinetics

A
  • Orally effective (except Tigecycline)
  • Insoluble chelates with multivalent cations decreasing oral absorption
  • Not admin with dairy, iron supplements, Mg laxatives & antacids/Pepto
  • Widely distributed in body (teeth, bone, placenta & breast milk)
20
Q

Tetracyclines Therapeutic Use

A
  • Broad spectrum Abx
  • G- & G+ (anaerobic & aerobic)
  • Oral Tx for acne
  • Prophylaxis for malaria
  • Effective against rickettsial infections, Chlamydia, Lyme disease, anthrax and Mycoplasma pneumoniae
21
Q

Tetracycline Adverse Reactions

A
  • GI irritation
  • Deposition in bones & teeth
  • Renal toxicity
  • Superinfection
  • Hepatotoxicity (pregnant especially)
  • Photosensitivity
22
Q

Macrolide Mechanism of Action

A
  • Bacteriostatic
  • Bactericidal with high doses or highly susceptible strains
  • Binds reversibly to 50S subunit (inhibits translocation of proteins elongation)
23
Q

Macrolide Resistance

A
  • Efflux transporters

- Methylation of 50S subunit decreases binding affinity

24
Q

Macrolide Therapeutic Uses

A
  • Atypical pneumonia

- Bordetella pertusis, diphtheria & chlamydia

25
Q

Macrolide Adverse Reactions

A
  • GI irritation
  • Prolonged QT interval
  • Cholestatic hepatitis with erythromycin estolate in adults