This page contains information on GentaFuse for veterinary use.
The information provided typically includes the following:
  • GentaFuse Indications
  • Warnings and cautions for GentaFuse
  • Direction and dosage information for GentaFuse


This treatment applies to the following species:
Manufacturer: Butler Schein™ Animal Health

Gentamicin Sulfate 100 mg/mL

For the control of bacterial infections of the uterus in horses

Also aids in improving conception in mares with uterine infection

Active against most gram-positive and gram-negative bacteria isolated from domestic animals - Pseudomonas aeruginosa, Staphylococcus species, Streptococcus species, Enterobacter species, Alcaligenes species, Proteus species


Each mL of GENTAFUSE (Gentamicin Sulfate) contains: gentamicin sulfate equivalent to 100 mg gentamicin base; 2.4 mg sodium metabisulfite; 0.8 mg sodium sulfite, anhydrous; 0.1 mg edetate disodium; 10 mg benzyl alcohol as preservative; water for injection q.s.


Gentamicin is a mixture of aminoglycoside antibiotics derived from the fermentation of Micromonospora purpurea. Gentamicin sulfate is a mixture of sulfate salts of the antibiotics produced in this fermentation. The salts are weakly acidic, freely soluble in water, and stable in solution.

Antibacterial Activity:

In vitro activity has shown that gentamicin is active against most gram-negative and gram-positive bacterial isolated from domestic animals.1 Gentamicin is active against Pseudomonas aeruginosa, indole-positive and -negative Proteus species, Escherichia coli, Klebsiella species, Enterobacter species, Alcaligenes species, Staphylococcus species, and Streptococcus species.


Studies in man indicate that recommended doses of gentamicin produce serum concentrations bactericidal for most bacteria sensitive to gentamicin within an hour after intramuscular injection; these concentrations last for 6 to 12 hours.2 Some 30% of the administered dose of gentamicin is bound by serum proteins and released as the drug is excreted.

Gentamicin is excreted almost entirely by glomerular filtration. High concentrations of the active form are found in the urine. Fifty to 100% of the gentamicin injected can be recovered unchanged within 24 hours from the urine of patients with normal renal function. A small amount is excreted into the bile.

Toxicity Studies:

No toxic effects were observed in rats given gentamicin sulfate 20 mg/kg/day for 24 days; in cats given 10 mg/kg/day for forty days. Gentamicin sulfate given to dogs at 6 mg/kg/day, 6 days weekly for 3 weeks, caused no detectable kidney damage. At higher doses, impairment of equilibrium and renal function were observed in these species.

GentaFuse Indications:

For use in horses only. GENTAFUSE (Gentamicin Sulfate) is recommended for the control of bacterial infections of the uterus (metritis) in horses and as an aid in improving conception in mares with uterine infections caused by bacteria sensitive to gentamicin.

Bacteriologic studies should be conducted to identify the causative organism and to determine its sensitivity to gentamicin sulfate.

Dosage and Administration

The recommended dose is 20 to 25 mL (2.0 - 2.5 grams) GENTAFUSE (Gentamicin Sulfate) per day for 3 to 5 days during estrus. Each dose should be diluted with 200-500 mL of sterile physiological saline before aseptic uterine infusion.


There are no known contraindications to this drug when used as directed.


If hypersensitivity to any of the components develops, or if overgrowth of non-susceptible bacteria, fungi, or yeasts occurs, treatment with GENTAFUSE (Gentamicin sulfate) should be discontinued and appropriate therapy instituted. Although gentamicin sulfate is not spermicidal, treatment should not be given the day of breeding.

GentaFuse Cautions:

Federal law restricts this drug to use by or on the order of a licensed veterinarian.


Not for use in horses intended for food.

Side Effects:

There have been no reports of drug hypersensitivity or adverse side effects following the recommended intra-uterine infusion of gentamicin sulfate combined with sterile physiological saline in mares.

How Supplied:

GENTAFUSE (Gentamicin Sulfate), 100 mg per mL for intra-uterine use is available in 100 mL and 250 mL multiple-dose vials.

Store between 2° and 30°C (36° and 86°F).

Protect from freezing.


1. Hennessey, PW, et al. In vitro activity of gentamicin against bacteria isolated from domestic animals. Veterinary Medicine/Small Animal Clinician. Nov. 1971; 1118-1122.

2. Black, J, et al. Pharmacology of gentamicin, a new broad spectrum antibiotic. Antimicrob Agents and Chemother. 1963; 138-147.

ANADA 200-115, Approved by FDA

NAC No.: 10822671

Telephone:   614-761-9095
Toll-Free:   1-855-724-3461
Every effort has been made to ensure the accuracy of the GentaFuse information published above. However, it remains the responsibility of the readers to familiarize themselves with the product information contained on the US product label or package insert.

Copyright © 2014 North American Compendiums. Updated: 2014-04-11