Monitoring
Serum creatinine
- Baseline
- Two – three times weekly
Aminoglycoside serum concentrations
- DO NOT ORDER serum peak concentrations
- Interval or trough level recommended in patients:
i. receiving > 3-5 days of aminoglycoside therapy
ii. with renal dysfunction and/or significant changes in renal function
iii. with a large volume of distribution (e.g. third spacing, ascites)
iv. > 65 years of age
v. concurrent nephrotoxic drugs (e.g. amphotericin B, cyclosporine)
- If levels are indicated, order an 8 hour interval level after first dose (if using Hartford nomogram), or a trough level at the end of the dosing interval. Repeat level at least once weekly. (May need more frequently if patient has renal dysfunction, i.e. requires q36h or q48h dosing; if renal function changing; or patient on concurrent nephrotoxic drugs.)
Aminoglycoside Therapeutic Drug Monitoring & Interpretation
| Antibiotic | Specimen | Order on Requisition | Sampling Times | Interpretation |
|---|---|---|---|---|
| Gentamicin and Tobramycin and Amikacin |
8 hour interval
OR |
Interval - 8h after dose start Amikacin - select "random" | 7-9 hours after START of infusion | Interpret in conjunction with Hartford Nomogram |
| Gentamicin and Tobramycin and Amikacin |
6-14 hour interval
OR |
Other | 6-6.9 or 9.1-14 hours after START of infusion | Interpret in conjunction with Hartford Nomogram |
| Gentamicin and Tobramycin and Amikacin | trough level | Trough | At the end of the dosing interval, i.e. 0-60 minutes before the next dose | AG trough level > 0.5-1mg/L suggests accumulation; lengthen dosing interval, or consider alternative antibiotic |
Ototoxicity
May be irreversible.
- Patients should be advised to watch for and report signs & symptoms of cochlear (e.g. tinnitus, sense of fullness in ears, loss of hearing) and/or vestibular (e.g. dysequilibrium, oscillopsia, cognitive dysfunction, visual sensitivity, nausea/vomiting, vertigo, headache, nystagmus) toxicity. AG should be discontinued immediately if any signs/symptoms of toxicity develop.
- Audiometry and vestibular testing recommended for patients receiving ≥ 7 days of aminoglycoside therapy, or at any time if ototoxicity suspected. Contact Audiology.