Infectious Disease Compendium

Aminoglycosides

Dosing

Aminoglycosides once a day.

By the way, aminolgycosides should probably be used as monotherapy only for urinary tract infections (PubMed).

Heres how its done, the rational follows:

Creatinine Clearance Formula

Gentamicin and Tobramycin Dose as follows and check a level at 12 or 18 h

Gentamicin and Tobramycin

CrCl

Interval (hour)

Dose (mg/kg)

12 h level (ug/ml)

18 h level (ug/ml)

100

24

5-7

1

<1

90

24

5-7

2

<1

80

24

5-7

2.5

<1

70

24

4

2

<1

60

24

4

3

1.5

50

24

3.5

3.5

1

40

24

2.5

3

1.5

30

48

2.5

4

2.5

20

48

4

4 (@ 24 h)

2 (@36h)

10

48

3

3 (@ 24 h)

3 (@36h

0

48

2

2 (@ 24 h)

6 (@36h

(Reference ) Creatinine Clearance Formula

Amikacin Dose as follows and check a level at 12 or 18 h

Amikacin

CrCl

Interval (h)

Dose

(mg/kg)

12 h level (ug/ml)

24 h level (ug/ml)

90

24

15

6

<1

70

24

12

9

2.5

50

24

7.5

7

3.5

30

48

4

7.5

5

20

48

7.5

7.4 @ 24 h

3.3 @ 36 h

10

48

4

12 @ 24 h

5 @ 36 h

0

48

3

16 @ 24 h

15 @ 36 h

The rational: Mostly used for gram negative infections. Aminoglycosides have dose dependent killing. More is better. Killing (of gram negative rods) depends on how high the peak is. Toxicity depends mostly on trough. By giving once a day drug, you maximize peak and killing and minimize trough and toxicity and is be supported by the literature. The oto toxicity may be decreasd with 1 gm po tid aspirin (PubMed).It also takes avantage of the post antibiotic effect of aminoglycosides where exposure to an aminoglycoside continues to inhibit bacterial growth after the aminoglycoside is removed from the medium. And with fewer levels and less frequent dosing it is cheaper and leads to decreased nursing time.