Dosing
Aminoglycosides once a day.
By the way, aminoglycosides should probably be used as monotherapy only for urinary tract infections (PubMed).
Heres how it is done, the rationale follows:
Gentamicin and Tobramycin Dose as follows and check a level at 12 or 18 h
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
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 supported by the literature.
It also takes advantage 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.
The ototoxicity may be decreased with 1 gm po tid aspirin (PubMed).
Curious Cases
Relevant links to my Medscape blog
Last Update: 04/08/19.