Gentamicin, SystemicDose, contraindications and adverse effects for Cats, Cattle, Dogs, Horses, Pigs and Poultry.

Aminoglycoside antibiotic; bactericidal against aerobic gram-negative bacteria by disrupting bacterial ribosomal protein synthesis. Although gentamicin is considered a first line agent in horses, the potential for toxicity of aminoglycosides limits their systemic (parenteral) use in other species to the treatment of serious infections when there is either a documented lack of susceptibility to other less toxic antibiotics or when the clinical situation dictates immediate treatment of a presumed gram-negative infection before

Gentamicin has a mechanism of action and spectrum of activity (primarily gram-negative aerobes) similar to the other aminoglycosides covering Escherichia coli, Klebsiella, Proteus, Pseudomonas, Salmonella, Enterobacter, Serratia, Shigella, Mycoplasma, and Staph- ylococcus.

Aminoglycosides are contraindicated in patients that are hypersensitive to them. Because these drugs are often the only effective agents in severe gram-negative and staphylococcal infections, there are no other absolute contraindications to their use. However, they should be used with extreme caution in patients with preexisting renal disease, with concomitant monitoring and dosage interval adjustments made.

Aminoglycosides’ nephrotoxic and ototoxic effects are well known. The nephrotoxic (tubular necrosis) mechanisms of these drugs are not completely understood but are likely related to accumulation in the renal convoluted tubules, interfering with phospholipid metabolism in the lysosomes of proximal renal tubular cells, and resulting in leakage of proteolytic enzymes into the cytoplasm.

■ Efficacy (cultures, clinical signs associated with infection) ■ Renal toxicity; baseline urinalysis, serum creatinine/BUN. Casts in the urine are often the initial sign of impending nephrotoxicity. Decreasing urine-specific gravity is an earlier indicator than azotemia.

A withdrawal interval is stated for this drug. It depends on the formulation, route and dose, so read the exact wording in the interactive drug guide before treating a food animal.