Inhibtors of protein synthesis

Question 1

Macrolides

Answer 1

Erythromycin- oral IV
Clarithromycin-oral
Azithromycin- oral IV

Question 2

Macrolides use

Answer 2

• Bind to 50S
• inhibition of protein syn G+
• Bacteriostatic: concentration and organism dependent - some cidal
• Oral with billiary excretion and fecal elimination

Question 3

Macrolides DOC

Answer 3

Chlamydia 
Mycoplasmal Pneumonia 
Syphillis 
Corynebacterium Diptheriae
Legionnaires disease

Question 4

Macrolides resistance

Answer 4

Methylation of the drug binding site (ribosome)

efflux pumps

Question 5

Macrolides toxicity

Answer 5

Erythro
-diarrhea, GI intolerance!!!
Clarithro: least GI side effects OT prolongation
- increased when coadministered with other drugs
Drug interactions inhibitor of CYP3A4!!
- Azithro is the least inhibiting of CYP

Question 6

Ketolides

Answer 6

Telithromycin

Question 7

Telithromycin mech

Answer 7

tighlty bind to two sites on ribosomal RNA instead of one

Question 8

Telithromycin

Answer 8

Oral  
Borad spectrum 
bacteriostatic
binds to 50s
- good against penumonia
* Black box warning!! for liver toxicity
* only for CAP

Question 9

Clindamycin use

Answer 9

oral parenteral and topical
50S
aerobic G+ cocci and some anerobic G- and G+
- bacteriorstatic and bactericidal (depending on organism)
metabolized by liver
- Strep and Staph
-**OSTEOMYALITIS
- toxic shock syndrome with vanco, nafcillin or first gen cephalosporin
-toxoplasma encephalitis

Question 10

Clindamycin toxicity

Answer 10

• • well known cause of Pseudomembranous colitis**- so if we see cdiff symptoms stop clindamycin
• skin rash, GI disurbances, abdominal pain, Vomiting
• *avoid when nursing

Question 11

Streptogramins mech

Answer 11

Dalforpristin - 50S
- early phase of protein syn 
 Quinupristin-50S 
-inhibits late phase of protein syn 
when adminitered togethr IV they act synergistically> Combination is bactericidal

Question 12

Dalforspristin and quinupristin use

Answer 12

aerobic G+ including

• penn resistnt s pneumoniae
• complicated skin and skin structur infection due to Staph MSSA and MRSA
• given IV

Question 13

Dalforspristin and quinupristin adverse

Answer 13

hepatotoicity, nausea/vomitng, itching
-inhibits p450
No for breast feeding, children, liver disease, preg, strepogramin hypersens

Question 14

Amnioglycosides mech

Answer 14

Bacterialcydal!!! because it hits multiple parts of the translation machinery

• Irreversibly inhibit portein synthesis at 30S subunit
• need active transport to bring into cell so we can only treat G- aerobic bacteria!!!

Question 15

Amnioglycosides mech

Answer 15

Bacterialcydal!!! because it hits multiple parts of the translation machinery
-Irreversibly inhibit portein synthesis at 30S subunit
- need active transport to bring into cell so we can only treat G- aerobic bacteria!!!
IM IV and topical
-dont really penetrate the CSF
- kidney is good at excreting

Question 16

Aminovlycosides spectrum

Answer 16

aerobic G- enteric bacteria or good for sepsis or endocarditis
Streptomycin: tularemia, plague, TB, endocarditis
Gentamicin/Tobramycin/amikacin: effetive agaisnt P. aeruginosa
Neomycin/gentamicin- topical application of wounds and burns caused by gram-neg organism
DOC: of enterococci!!! when in combo with penicillin
** has a post-antibiotic effect!

Question 17

Aminoglycosides toxicity

Answer 17

ototoxicity and nephrotoxicity!!!!! - particulally dependednt on time and concentration of the drug
very severe
- GI upsets, overgrowth of non suspetible organisms, nausea, weakness,

Question 18

Aminoglycosides Cross resistance

Answer 18

Bacteria that acquire resistance to one aminoglycoside may be resistance to other aminoglycosides

• deficiency of ribosomal receptors
• lack of permiability of the drug into the bacteria
• enzymatic modification by the bacteria

Question 19

Broad Spectrum Abx group

Answer 19

Chloramphenicol
tetracyclines
glycylcylines

Question 20

Chloramphenicol spectrum

Answer 20

Static and best for spectrum-
50S
Spectrum: pretty much everything
Not first choice super toxic!
ex: Typhoid, Menengitis, Rickettsia, Brucellosis, RMSF, Melioidosis
- leading bacterial topical conjunctivitis

Question 21

Chloramphenicol Pharmacokinetics

Answer 21

Parenteral
Distributed widely- eyes and CNS!!!! best CNS
- 90% met by liver conjucatted with glucuronic acid to be eliminated
- excreted by the kidney
- inh of CYP 3A4 2C19

Question 22

Chloramphenicol Tocicities

Answer 22

• dose dependent: bone marrow suppression> reversable upon discontinuation
• dose independent: fatal aplastic anemia (fatal)> can develop after drug is discontinued
• Grau baby syndrome: they dont have glucuronyl transferase in premature or newborn liver so it cannt be eliminated

Question 23

Chloramphenicol resistance

Answer 23

production of acetyl transderate inactivates the drug
efflux pimp
bidning site may be modified

Question 24

Tetracyclines

Answer 24

tetracyclines -oral/ top
doxycyclines-oral
minocycline-oral

Question 25

Tetracyclines mech/spec

Answer 25

``` 30S static! Broad spectrum! DOC- see the slide/chart - early lymes and RMSF -mycoplama pneumonia -clamydia -DOC for cholera ```

Question 26

Tetracyclines resistance

Answer 26

Efflux pumps *cross resistance doesnt exist becuase the pumps are different tetra is the most suseptable

Question 27

Tetracyclines adverse

Answer 27

- normal flora changes- GI - bone and teeth deposit/ inh bone growth> no to preg an 8yrs - liver damage - fanconi syndrome - photosensitivity*

Question 28

Glycylcyclines

Answer 28

Tigecycline> think of it as a tetracycline 30S IV only - good for tetracycline resistant organisms

Question 29

Ozaolidinones

Answer 29

Linezolid

Question 30

Linezolid spec

Answer 30

``` IV G+ aerobes - pneumonia, skin inf, VRE, MRSA -drug of last resort 50s static except for streptococci which its cidal *** inhibitor of MOA*** ```

Question 31

Linezolid kinetics and adverse

Answer 31

IV and metabolized via oxidation but doesnt need hepatic enzymes Adverse - N/V/D/HA -MOA inhibitos!!! ** cannot give to patients with phenochromocytoma

Question 32

Linezollid drug int

Answer 32

B blockers, anesthetics, any antidepresant, tyramine rich foods (aged cheese, pickled)