Doses - GENTAMICIN SULFATE
For small animals, one pair of authors (Aronson and Aucoin 1989) make the following recommendations with regard to minimizing risks of toxicity yet maximizing efficacy:
Dogs: 
For susceptible infections: a) 2.2 - 4.4 mg/kg IV (only if acute sepsis) or IM q8h; see recommendations above fordosage/interval adjustment. (Aronson and Aucoin 1989)
b) 2 - 4 mg/kg IV, IM or SubQ q8h (avoid use or reduce dosage in patients with renalfailure; recommend therapeutic drug monitoring, particularly in young animals) (Vadenand Papich 1995)
Cats: 
For susceptible infections: a) 2.2 - 4.4 mg/kg IV (only if acute sepsis) or IM q8h; see recommendations above fordosage/interval adjustment. (Aronson and Aucoin 1989)
b) 2 - 4 mg/kg IV, IM or SubQ q8h (avoid use or reduce dosage in patients with renalfailure; recommend therapeutic drug monitoring, particularly in young animals) (Vadenand Papich 1995)
c) 3 mg/kg IV, SQ q8h (Jernigan et al. 1988)
Pocket Pets/Rodents:
For empiric antibiotic therapy:
a) 5 mg/kg once daily IM or SubQ (Oglesbee 1995)
Cattle: 
For susceptible infections: a) 4.4 - 6.6 mg/kg/day IM divided tid (Upson 1988)
b) Intramammary: 100-150 mg q12h (Schultz 1986)
c) 2.2 mg/kg q12h (McConnell and Hughey 1987)
d) 5 mg/kg IM q8h (Haddad et al. 1987)
Horses: 
For susceptible infections: a) 1 - 3 mg/kg IM qid (Robinson 1987)
b) For gram negative respiratory infections: 2.2 mg/kg IM or IV 4 times a day in maturehorses and 3 times a day in foals. (Beech 1987a)
c) In foals: 2 - 3 mg/kg IV q12h; use lower dose in premature foals or those less than 7days of age. Monitor serum levels if possible. (Caprile and Short 1987)
d) For prophylaxis (with penicillin G) for surgical colic: 2.2. mg/kg tid IV. (Stover 1987)
e) 2.2 mg/kg IV q6h; animals must be well hydrated. (Sweeney et al. 1988)
f) 2 - 4 mg/kg IM q8-12h (Baggot and Prescott 1987)
g) 4.4 mg/kg IV q12h (Duran 1992)
h) There is increased interest in giving gentamicin once daily at an initial dosage of 6.6mg/kg preferably as an IV infusion over one hour. Therapeutic drug monitoring wouldbe beneficial. Watch for futher references documenting the safety and efficacy of thisdosing method. (Plumb)
Swine: 
For susceptible infections: a) For colibacillosis in neonates: 5 mg PO or IM once (Label directions; Garacin® Pig
Pump and Piglet Injection¯Schering)
b) For weanling and other swine:
Colibacillosis: 1.1 mg/kg/day in drinking water (concentration of 25 mg/gallon) for 3days.
Swine dysentery (Treponema hyodysenteriae): 2.2 mg/kg/day in drinking water(concentration of 50 mg/gallon) for 3 days. (Label directions; Garacin® Soluble
Powder & Oral Solution¯Schering)
Birds: 
For susceptible infections: a) For Pheasants and Cranes: 5 mg/kg IM tid for 5-10 days. For Quail, African Grey
Parrots: 10 mg/kg IM tid. Blue and Gold McCaws: 10 mg/kg IM bid. Once or twicedaily dosing may be effective in less serious infections. (Clubb 1986)
b) For gut sterilization/gut infections: 40 mg/kg PO 1-3 times a day for 2-3 days. (Clubb1986)
c) For pneumonia (with carbenicillin or tylosin given IM): 5 - 10 mg/kg intratracheallyonce daily. (Clubb 1986)
Reptiles: 
For susceptible infections: a) For bacterial gastritis in snakes: gentamicin 2.5 mg/kg IM every 72 hours with oral neomycin 15 mg/kg plus oral live lactobacillus. (Burke 1986)
b) For bacterial shell diseases in turtles: 5 - 10 mg/kg daily in water turtles, every other day in land turtles and tortoises for 7-10 days. Used commonly with a beta-lactam antibiotic.
Recommend beginning therapy with 20 ml/kg fluid injection. Maintain hydration and monitor uric acid levels when possible. (Rosskopf 1986)
Monitoring Parameters (parenteral use)-
Client Information - With appropriate training, owners may give subcutaneous injections athome, but routine monitoring of therapy for efficacy and toxicity must still be done. Clients shouldalso understand that the potential exists for severe toxicity (nephrotoxicity, ototoxicity) developingfrom this medication.
Dosage Forms/Preparations/FDA Approval Status/Withholding Times - Veterinary-Approved Products:
Gentamicin Sulfate Injection 50 mg/ml & 100 mg/ml (horses only) in 50 ml & 100 ml vials ;
Gentocin® (Schering);Ultragex® 100 (Anthony); Generic (Rx) Approved for use in dogs, cats, and horses (not for food).
Gentamicin Sulfate Injection 5 mg/ml in 250 ml vials; Garacin® Piglet Injection (Schering); (OTC) Approved for use in swine. Slaughter withdrawal = 40 days.
Gentamicin Sulfate Oral Solution 50 mg/ml in 80 ml bottles; Garacin® Oral Solution (Schering); (OTC) Approved for use in swine. Slaughter withdrawal = 3 days.
Gentamicin Sulfate Oral Solution 4.35 mg/ml in 115 ml pump bottles (1 pump delivers approximately 5 mg); Garacin® Pig Pump Oral Solution (Schering); (OTC) Approved for usein swine. Slaughter withdrawal = 14 days.
Gentamicin Sulfate Soluble Powder 2 g gentamicin/30 grams of powder in 360 gram jar or 2 ggentamicin in 120 gram packets; Garacin® Soluble Powder (Schering); (OTC) Approved foruse in swine. Slaughter withdrawal = 10 days.
Veterinary-approved injections for chickens and turkeys plus a water additive for egg dipping areavailable. Ophthalmic, otic and topical preparations are also available with veterinary labeling.
Human-Approved Products (partial listing):
Gentamicin Sulfate Injection 40 mg/ml & 10 mg/ml as sulfate and 2 mg/ml as sulfate in 2 & 20ml vials and 1.5 & 2 ml cartridge-needle units/disp. syringes and 2 ml amps; Garamycin®(Schering); Jenamicin® (Hauck); Pediatric Gentamicin Sulfate® (Elkins-Sinn; Garamycin
Pediatric® (Schering); Garamycin Intrathecal® (Schering); generic, (Rx)
Topical, otic and ophthalmic labeled products are also available.