Aminoglycosides are broad-spectrum antibiotics, effective against gram-negative bacteria.
Aminoglycosides urine concentration exceeds that of the plasma by up to a hundred. Their
efficacy is dependent on their level above minimal inhibitory concentration (MIC); however
high levels are associate with nephrotoxicity. Therefore aminoglycosides have a narrow
therapeutic rang. The correlation between administrated dose and blood drug levels is hard to
predict. Amikacin is a highly effective aminoglycoside, highly effective against extended
spectrum beta lactamase (ESBL) bacteria.
Older patients suffer from more urinary tract infection (UTIs), and have a higher frequency
of infection with resistant bacteria, mainly among frail nursing home residents.
Our goal is to prove that fixed low dose amikacin in the elderly patient in non-inferior to
weight-adjusted treatment.
Study design:
A randomized prospective, open label, non-inferiority trial
Study participants will be 65 years or older, who were admitted to the medical ward due to a
UTI will be assigned to one of the following study arms:
1. Intervention arm: in which patients will receive a fixed dose of amikacin, 500 mg, once
a day.
2. Comparator arm: in which patients will receive a weight adjusted dose of amikacin (15
mg/kg adjusted body weight) and continue in adjusted intervals according plasma
concentrations, using the Barnes Jewish Hospital nomogram.
All participants will be followed up with:
1. Amikacin blood levels 6-14 hours following first administration, used for dose
adjustment according to the nomogram. Peak amikacin blood levels, 30- 60 minutes
following first or second administration.
2. Urine analysis and culture upon admission to the emergency department (ER). In patients
with indwelling urinary catheters, cultures will be taken following replacement with a
new catheter.
3. Broad serum biochemistry, complete blood count, C-reactive protein and blood cultures
will be taken upon admission to the ER, two days after recruitment and at least once
every three days following that, as long as the patient is receiving amikacin.
Duration of amikacin treatment will be according to the attending physician's clinical
judgment; however, it will not be shorter than 72 hours since first dose. Total duration of
amikacin treatment will not exceed 10 days. Total treatment for UTI will not fall short of
seven days of antibiotics (either amikacin or any suitable alterative according to blood
and/or urine cultures).