test 6 protein synthesis inhibitors

Question 1

Protein Synthesis Inhibitors: Aminoglycosides drugs

Answer 1

› Neomycin
        – Only used topically
› Streptomycin
        – Little used, lots of resistance
› Gentamicin
› Amikacin
        – Least bacterial resistance

Question 2

Protein Synthesis Inhibitors: Aminoglycosides

Answer 2

› Protein synthesis inhibitors are general bacteriostatic, HOWEVER, aminoglycosides are bactericidal
› Bactericidal effect is concentration dependent
› Derived from
– Streptomyces sp. (end in –mycin)
– Micromonospora sp. (end in –micin)
› Inhibit bacterial protein synthesis by binding to the 30S ribosomal subunit

Question 3

Aminoglycosides effective on

Answer 3

› Majority of gram negative bacilli, including
– P. aeruginosa
– Klebsiella pnuemoniae
– Enterobacter sp.
– Often combined with β-lactam antibiotics!
› Synergistic effect

Question 4

Aminoglycoside Pharmacokinetics

Answer 4

› Absorption
– All aminoglycosides given parenterally or topically for skin infections
› Distribution
– Do not penetrate into CSF, even in presence of inflamed meninges
– Cross placental barrier and concentrate in fetal plasma and amniotic fluid
› Elimination
– Kidney
– More toxic in the presence of renal failure

Question 5

Aminoglycosides: Adverse Effects

Answer 5

› Ototoxicity
– Directly related to plasma levels and duration of treatment
– May be irreversible
– Can affect fetus
› Nephrotoxicity
– Mild reversible impairment to severe tubular necrosis
› Neuromuscular paralysis
– Associated with rapid increase in plasma levels
– Myasthenia gravis patients particularly at risk

Question 6

Protein Synthesis Inhibitors: Macrolides

Answer 6

› Inhibit bacterial protein synthesis by binding to the 50S ribosomal subunit
› Azithromycin (Zithromax Z-Pak)