Gentamicin and Amikacin

Question 1

Therapeutic Range

Answer 1

Therapeutic Range: For multiple daily dose regimens, one-hour (peak) serum concentration should
be 5 to 10mg/L (3 to 5 mg/L for endocarditis), pre-dose (trough) concentration should be < 2mg/L
(< 1mg/L for endocarditis); For once-daily dose regimens, consult local guidelines.
Loading doses may be required

Question 2

Major route of elimation

Answer 2

Renal excretion

Question 3

Monitoring

Answer 3

Renal function (nephrotoxicity), auditory and vestibular function (ototoxicity which is irreversible),
serum-aminoglycoside concentration must be determined in the elderly, those with renal impairment,
if high doses given, obesity and in cystic fbrosis

Question 4

Warning signs

Answer 4

Hearing impairment or hearing disturbance

Question 5

Actions required

Answer 5

• Advise patient to report immediately to a doctor if any of the warning signs occur
• Ensure patient is hydrated and drinking adequate amounts of fuid to prevent dehydration
before starting treatment

Question 6

Interactions

Answer 6

• Increased risk of nephrotoxicity when aminoglycosides such as gentamicin are given with
ciclosporin, tacrolimus, vancomycin
• Increased risk of ototoxicity when aminoglycosides given with loop diuretics, vancomycin