Target species
Horses (non food producing horses).
Indications for use
For the treatment of infections of the lower respiratory tract in horses caused by aerobic Gram-negative bacteria susceptible to gentamicin.
Contraindications
Do not use in known cases of renal dysfunction.
Do not use in cases of known hypersensitivity to the active substance or to any of the excipients.
Do not exceed the proposed dosing regimen.
Special warnings for each target species
Do not use in horses which are intended to produce meat or milk for human consumption.
Special precautions for use in animals
Horses:
Gentamicin is well known to induce nephrotoxicity even at therapeutic doses. There are also isolated reports of ototoxicity with gentamicin. No margin of safety has been established under the approved dosing regimen. As such, gentamicin has a narrow margin of safety. The product should therefore only be used based on the benefit:risk assessment by the responsible veterinary surgeon for each individual horse, taking into account alternative available treatment.
In order to reduce the nephrotoxic risk, adequate hydration of animals under treatment should be ensured, and fluid therapy should be instituted, if required. Close monitoring of horses being treated with gentamicin is strongly advised. This monitoring includes assessing relevant kidney parameters in blood (e.g. creatinine and urea) and urinalysis (e.g. gamma glutamyl transferase/creatinine ratio). Therapeutic blood monitoring of gentamicin concentration is also recommended because of known individual animal variations in peak and trough gentamicin plasma concentrations. Where blood monitoring is available, target peak plasma gentamicin concentrations should be approximately 16-20 µg/ml.
Particular caution should be taken when administering gentamicin with other potential nephrotoxic medicinal products (containing e.g. NSAIDs, forusemide and other aminoglycosides).
Safety of gentamicin has not been established in foals and there is a lack of knowledge of the extra effects of gentamicin on foal kidneys, especially neonates. Current knowledge suggests that foals, especially neonates, are at a higher risk of gentamicin-induced nephrotoxicity compared to adults. Differences between neonatal foal kidneys and adults include a slower clearance of gentamicin in foals.
As such, no margin of safety has been established in neonatal foals. It is therefore not recommended to use the product in foals.
Whenever possible, use of the product should be based on susceptibility testing of the bacteria isolated from the animal. Gentamicin is a narrow-spectrum Gram-negative bactericidal antimicrobial, without effects on anaerobe bacteria and mycoplasmas. Gentomicin does not penetrate intracellularly, or into abscesses. Gentamicin is deactivated in the presence of inflammatory debris, low oxygen environments and low pH.
The dosing regimen must not be exceeded. Use of the product deviating from the instructions given in this datasheet increases the risk of nehprotoxicity and may increase the prevalence of bacteria resistant to gentamicin.
Extra caution is advised if using gentamicin in old horses, or with fever, endotoxemia, sepsis and dehydration.
Special precautions to be taken by the person administering the veterinary medicinal product to animals
Gentamicin may cause hypersensitivity (allergic) reactions following exposure. People with known hypersensitivity to gentamicin should avoid contact with the product. Administer the product with caution. In case of accidental self-injection, seek medical advice immediately and show the package leaflet or the label to the physician.
Adverse reactions
Hypersensitivity reactions have been reported very rarely following the use Genta- Equine 100 mg/ml Solution for Injection for Horses.
A local reaction may occur at the injection site, especially in case of repeated injections in adjacent sites. See Special precautions for use in animals.
The frequency of adverse reactions is defined using the following convention:
- very common (more than 1 in 10 animals treated displaying adverse reaction(s))
- common (more than 1 but less than 10 animals in 100 animals treated)
- uncommon (more than 1 but less than 10 animals in 1,000 animals treated)
- rare (more than 1 but less than 10 animals in 10,000 animals treated)
- very rare (less than 1 animal in 10,000 animals treated, including isolated reports).
Use during pregnancy and lactation
The safety in pregnant horses is unknown. However, studies in laboratory animals have shown evidence of foetal nephrotoxicity. Use only based on the benefit:risk assessment by the responsible veterinarian.
Interactions
This product should not be used in conjunction with other aminoglycoside antibiotics, or with other drugs known to induce either ototoxicity or nephrotoxicity.
Amounts to be administered and administration route
Horses:
Intravenous use.
Single dose of 6.6 mg/kg body weight given intravenously once daily for 3-5 consecutive days.
To ensure a correct dosage, body weight should be determined as accurately as possible to avoid under or overdosing. The dosing regimen must not be exceeded.
The use of gentamicin in foals and neonates is not recommended.
Overdose
The product was not specifically tested in overdose studies and therefore, no margin of safety has been determined.
Withdrawal periods
Not authorised for use in horses producing meat or milk for human consumption.