When I diagnose an infection in a patient, I must prescribe antibiotics. For the person who lives with the pet, that can mean a week or more of giving pills (or a liquid formulation) at home. Under the best circumstances, giving medicine to pets is inconvenient. In the worst cases, it is impossible.

However, a new antibiotic has been approved for use in cats and dogs. It may eliminate the need to give pills at home when pets are diagnosed with certain types of infections.

The antibiotic, called Convenia, was released earlier this year by Pfizer. It is given by injection at the vet’s office. Each injection is effective for up to two weeks. Pets that receive Convenia do not need to take antibiotics at home.

Convenia has two other advantages over conventional antibiotics. First, studies have shown that side effects occur less often with Convenia than with comparable oral antibiotics.

Second, antibiotic-resistant strains of bacteria may be less likely to develop when pets are treated with Convenia. Improper dosing (skipping doses or stopping the medication too soon) is a leading factor in the evolution of antibiotic resistance. Pets that receive Convenia are virtually assured of proper dosing.

So, are vets going to stop stocking other types of antibiotics now that Convenia has hit the market? No. There are two sides to every coin, and I can see a few potential disadvantages to the new medicine.

First, Convenia is not effective against all types of infections. It is labeled for skin infections, wounds and abscesses only.

Also, when a pet develops side effects from oral antibiotics, the medicine can be stopped. Side effects from Convenia are rare. However, if they develop there is no way to discontinue treatment or remove the drug from the pet’s body.

Finally, as a veterinarian I am wary of giving too many injections to cats. This stems from the link between some vaccines and certain types of tumors. Convenia has not been linked to tumors in cats. Nonetheless, I plan to be cautious until the drug has been on the market for a while longer.

The bottom line is that Convenia isn’t perfect. But no medicine is. Convenia may prove to be very useful indeed.