Aminoglycoside contraindications and precautions and suggested monitoring for toxicity (Box 2.5)
Aminoglycosides should not be used in patients with:
previous vestibular or auditory toxicity due to an aminoglycoside
serious hypersensitivity reaction to an aminoglycoside (rare).
Unless there is no appropriate safer alternative, aminoglycosides should be avoided if treatment is likely to extend for longer than 48 to 72 hours in patients with:
pre-existing significant conductive hearing problems
pre-existing vestibular problems (including dizziness, vertigo or tinnitus)
neuromuscular disorders (including myasthenia gravis, parkinsonism)
chronic liver disease, severe cholestasis (serum bilirubin >90 micromol/L)
chronic renal failure or deteriorating renal function.
Monitoring (see also Monitoring of gentamicin in patients with endocarditis)Nephrotoxicity
Serum creatinine should be checked, and creatinine clearance calculated before commencing an aminoglycoside (to determine appropriate starting dose, see Table 2.25, Table 2.26, Table 2.27) and then 2 to 3 times each week, or more frequently if renal function is very unstable.Ototoxicity
Patients should be informed where possible that there is a chance of balance or hearing problems related to aminoglycoside use, especially if treatment is prolonged. Patients should be regularly asked about any hearing or balance problems and told to report immediately if they occur. For prolonged aminoglycoside courses (>5 days), formal vestibular function testing and high-frequency audiometric testing should be considered, if available.
Routine monitoring of aminoglycoside plasma levels is recommended for all patients who are likely to receive aminoglycosides for more than 2 days The aim is to delay the onset of nephrotoxicity, and reduce the risk of vestibular and auditory ototoxicity, as well as ensuring adequacy of dosing. While nephrotoxicity is usually reversible, ototoxicity is much less commonly reversible. Monitoring of plasma levels will not prevent the sudden idiosyncratic deafness that is rarely observed