Tobradex is the brand name for a combination of the antibiotic tobramyacin and the gluticosteroid dexamethasone. Tobradex is made by Alcon Labs. However, Tobradex is a medication made for treating human eye infections. It is not specifically made for dogs, but many vets turn to it to treat eye infections in dogs.
The tobramycin aggressively kills any bacteria invading a dog's eye. But the dog's natural immune responses may mistake the tobramycin as an invader and destroy it before it can kill the invading bacteria. Therefore, the dexamethasone is added to suppress the dog's immune system so the tobramycin can kill the bacteria.
Tobradex comes in eye drops and eye ointment. According to Alcon, the manufacturer, each millimeter contains 0.3% tobramycin and 0.1% dexamethasone. The drops need to be shaken before use in order to be sure because the active ingredients settle to the bottle's bottom. Both of these can only be purchased with a prescription from your veterinarian.
Because Tobradex is a human drug, there are no dosage standards set up for dogs. The dosage amount is determined by the veterinarian for the particular dog's needs. The goal is to give the smallest possible amount that will both control the infection and yet not produce bad side effects. Even The Pill Book Guide to Medication for Your Dog and Cat (Kate A.W. Roby, VMD, et al; 1998) will not give a dosage recommendation.
Possible side effects that would happen right away are itchy eyes, swollen eyelids, facial swelling, severe diarrhea and vomiting. Possible long term side effects include a secondary infection because of the suppression of the immune system, deafness, coordination problems resulting from inner ear damage, kidney damage or liver damage. Tobradex may also cause a dog already on diuretics to become quickly dehydrated.
Because of the risks of deafness and loss of coordination, Tobradex should not be given to therapy dogs, search and rescue dogs, dogs that work on farms or ranches, pregnant dogs, nursing dogs or puppies. Because of the risk to the kidneys and liver, dogs with liver or kidney problems or very old dogs should not be given Tobradex.