Aminoglycosides

Question 1

Aminoglycosides MoA

Answer 1

After being transported into the cell in an O2-dependent process,

Irreversibly bind and inhibit 30S subunit.
Bacteriocidal - the other 30S inhibs are static.

Effect depends on the Cmx:MIC ration being at least 8-10. Higher ratio increases potency (and ototoxicity)

Question 2

Aminoglycosides toxicity

Answer 2

Reversible Nephrotoxicity, which is dependent on the trough and time over MIC, why it is given once per day.

Irreversible Ototoxicity dependent on the Cmax value.

Possible allergic reaction

Neuromuscular blockade under anesthesia

Question 3

Aminoglycoside drug names

Answer 3

in order of increasing efficacy.
Streptomycin

Gentamycin

Tobramycin

Amikacin

Question 4

Aminoglycoside spectrum and indications

Answer 4

Spectrum For G-Negative AEROBES, resistant aerobes
Pseudomonas, Klebsiella, Enterobacter.

Tobramycin for pseudomonas

2nd line for Tuberculosis
Tobramycin

Due to its renal accumulation also effective as monotherapy for UTIs

Synergistic effect with beta-lactams, especially for Enterococcal infections and infective endocarditis.

Neomycin for topical creams.