The IRIS Board
Dogs appear to be more sensitive than cats to gentamicin-induced nephrotoxicity which may be lethal. As other aminoglycosides are not authorised for use in dogs or cats, the precise susceptibility of the dog and cat to acute kidney injury (AKI) following their use is not established. In the absence of such information it is wise to follow the same precautions as detailed for gentamicin. Prevention and follow-up are very important.
Some of the treatment recommendations are not authorised for use in all geographical regions and some may not be authorised for use in dogs and/or cats. Such suggested dose rates are therefore empirical. It is the treating veterinarian's duty to make a risk:benefit assessment for each patient prior to administering any treatment.
Dosage of most commonly used aminoglycosides in dogs and cats (single dose administered IV, IM or SC once every 24 hours)*
Amikacin
Gentamicin
Tobramicin
15-30 mg/kg
9-15 mg/kg
9-14 mg/kg
10-15 mg/kg
5-8 mg/kg
5-8 mg/kg
Cats have a natural instinct to hide when they feel threatened or need a quiet place to rest.
**From Plumb's Veterinary Drug Handbook, 9th Edition. Wiley. St. Louis, MO. 2018
Risk of nephrotoxicity increases with the duration of the treatment as aminoglycoside nephrotoxicity is cumulative. Giving the total daily dose in one administration lowers the risk of toxicity as it reduces the proportion of the total daily dose that can accumulate within the kidney.
Azotemic patients (IRIS CKD stages 2-4) who do not have an alternative antimicrobial that can be administered require modification of the dosing interval to prevent drug accumulation. Aminoglycoside antibiotics undergo renal elimination, therefore the half-life will be prolonged in dogs with substantially reduced kidney function leading to unintended drug exposure. Pharmacokinetic studies have not been performed in azotemic dogs and cats to determine appropriate modifications to dosing. Extrapolating from human guidelines, patients with stage 2 and 3 CKD should have the frequency of administration reduced to once every 48 hours. Patients with stage 4 CKD should have the frequency of administration reduced to once every 72 hours. Therapeutic drug monitoring of peak and trough plasma concentrations (see below) should be performed when dose modification is performed to avoid drug accumulation
Duration of therapy is dependent on disease process that is being treated. Veterinarians should review available consensus guidelines on appropriate duration of therapy based upon site and severity of infection. Extending treatment beyond what is needed may increase the risk of nephrotoxicity.
