JAL L6 Inhibitors of protein synthesis Flashcards
Inhibitors of protein synthesis tend to be static or cidal?
Static
Inhibitors of cell wall synth cause the most problems because…
Process is similar in eukaryotes, therefore toxic effects
Ribosomal ‘s’ is a unit of ….
density
e.g. of aminoglycosides?
gentamycin
Aminoglycosides are for aerobic or anaerobic?
aerobic (e.g septacimia, complicated UTI, nosocomial RTI)
Aminoglycosides are for gram ….
-ve, also some +ve
Aminoglycosides bind ……..
mode of action……
bind to 30S subunit
reduce assembly of the initiation complex
Aminoglycosides penetrate inside cells?
No. Poor penetration in CSF too.
Cross the placenta though.
Aminoglycosides are administered via…
IV, IM, or topically for wounds.
Not absorbed by the gut.
s/e Aminoglycosides
Nephrotoxic
Ototoxic
Oxazolidinones e.g.
linezolid
Oxazolidinones are active against gram
+ve
Oxazolidinones are active against what evil disease
MRSA (and vancomycin resistant enterococci)
Linezolid binds to …..
mode of action….
23S rRNA in 50S subunit
reduces assembly of the initiation complex
Linezolid is administered…
orally or IV
s/e of linezolid
GIT hypersensitivity headache SEVERE: pseudomembranous colitis allergy thrombocytopenia pancytopenia neuropathy
Tetracyclines are broad or narrow spectrum?
broad
e.g. of Tetracyclines
doxycycline
Tetracyclines given orally for….
RTI, acne, chlmydia
Many ……….(2)……….. species are now resistant to tetracyclines
Staph and strep
Tetracyclines bind to….
mode of action
30S ribosomal subunit
Reduces tRNA binding to site A
Tetracyclines are administered…
orally (although absorption is reduced by cations)
Tetracyclines are distributed to the fetus?
and the CSF?
Y
N
s/e Tetracyclines
GIT irritant superinfection deposition forming in bones/teeth kidney and liver damage phototoxicity
An alternative to penicillin for treating strp. infections
macrolides/ketolides
e.g. of a macrolide
erythromycin
Uses of macrolides
RTI, STI, GIT
Macrolides are administered…
orally (or IV)
e.g. of ketolides?
Telithromycin
Ketolides are just more potent….
macrolides (designed to overcome resistance)
Macro/ketolides bind to….
mode of action….
50S subunit
Reduce translocation and release of tRNA
Are Macro/ketolides well distributed?
yes (not CSF)
Macro/ketolides are …………… liable therefore enteric coated?
acid-liable
Macro/ketolides s/e
GIT (superinfections) cholestatic jaundice reversible ototoxicity allergic reactions cardiac effects
Lincosamides e.g.
clindamycin
Uses of Lincosamides
IV, IM or orall for staph bone and joint infections RTI peritonitis septicaemia
Lincosamides s/e
antibiotic associated diarrhoea
Fusidic acid is broad or narrow spec?
Narrow, for STAPH infecttions
Fusidic acid binds to…
mode of action….
EF-G-ribosome complex
reduces translocation of tRNA
Uses of fusidic acid…
topically for skin and eye infections
orally and IV for osteomyelitis and endocarditis
Chloramphenicol is broad or narrow spec
broad
Chloramphenicol is used….
topically for eye infections
orally or IV for meningitis, typhoid - potentially fatal s/e when iv
Chloramphenicol binds to….
mode of action….
50s subunit
prevents peptide bond formation
Chloramphenicol penetrates what tissues
all well, including the brain
Chloramphenicol s/e
bone marrow supression Grey baby syndrome GIT peripheral and optic neuritis aplastic aneamia
Chloramphenicol is not suitable under what age
4 years
aplastic anemia is….
bone marrow stem cells die. Normal haemopoietic cells absent and space filled with adipose tissue.
