Sulfamethoxazole Trimethoprim antibiotics are designed to counter a variety of bacterial infections in pets. Its ingredients fight against infections in your pet’s urinary tracts, respiratory systems, gastrointestinal areas, skin, and much more. Since these conditions can lead to great pain and discomfort in your pets, it is important to identify the cause and get appropriate treatment for them right away. This is an oral antibiotic for pets, and it can be mixed with food during feeding time. SMZ-TMP Rx is a veterinarian-prescribed medication. Be sure to follow your vet’s instructions when using SMZ-TMP Rx.