Aminoglycosides

Question 1

General mechanism of action for aminoglycosides?

Answer 1

Irreversible inhibition of the 30S subunit of bacterial ribosomes

Question 2

What are the 4 aminoglycosides?

Answer 2

Gentamicin
Tobramycin
Amikacin
Streptomycin

Question 3

Gentamycin is most effective against what organisms?

Answer 3

Gram Positives - Group Strep, Strep viridians, Staph aureus, Enterococcus
Gram Negatives- E coli, Enterobacter, Proteus, Citrobacter, Serratia

Question 4

Gentamycin toxicity?

Answer 4

Generally considered the most nephrotoxic

Question 5

Tobramycin is most effective against which organisms?

Answer 5

Pseudomonas aeruginosa

Slightly less active against other Gram Negatives

Question 6

Amikacin is generally most effective against which organisms?

Answer 6

Generally more active against nosocomial Gram negatives
Mycobacterium - Mtb, atypical Mycobacteria
Nocardia

Question 7

Streptomycin generally used for what organisms?

Answer 7

Enterococcus (only when gentamicin isn’t available)

Mtb

Question 8

How are aminoglycosides eliminated?

Answer 8

99% renal elimination

Question 9

What is the aminoglycosides’ efficacy dependent on?

Answer 9

Concentration dependent killing

The peak/MIC is generally proportional to efficacy. The time above the MIC does not matter for aminoglycosides.

Question 10

Traditional vs. Extended Interval Dosing

Answer 10

Extended Interval dosing (one big dose once per day) is more effective, less nephrotoxic, longer post antibiotic effect, cost saving, and more intuitive for the concentration dependent bactericidal killing with aminoglycosides.

Question 11

Two major toxicities of aminoglycosides

Answer 11

Nephrotoxicity and Ototoxicity