Antibiotic overdose

WHAT'S THE first thing you do when you're feeling sick or your pet has diarrhea? Ask your doctor or vet to prescribe antibiotics to knock down whatever it is quickly?

That's a common request in human and veterinary medicine, but it's not necessarily the right one. From urinary tract infections to dental disease, antibiotics seem to be the easy answer, but their overuse in animals and humans is creating resistant bacteria. Instead of being killed off by the drugs, bacteria continue to multiply, becoming stronger than ever. That makes them ever more difficult to treat. And often, they are not even necessary.

"Lots of ailments that we see are caused by viruses, which antibiotics won't do anything for," says Tony Johnson, DVM, an emergency and critical-care specialist. "Lots of ailments that we see are going to go away on their own without antibiotics. We prescribe antibiotics for things that there's absolutely no need for. If a dog gets hit by a car and doesn't have a mark on it, he doesn't need antibiotics. If a dog has a cut less than the size of a dime, it'll heal on its own; he doesn't need antibiotics. Veterinarians are as guilty of this as the general public."

A review of antibiotic use in dogs, published in June 2011 in the Journal of Small Animal Practice, found that there was a confirmed infection in only 17 percent of the prescriptions. In 45 percent, infection was suspected; for instance, the patient had an open wound or discharge from the eyes or nose. In 38 percent, there was no documented evidence of infection. In those cases, the antibiotics were often given for "preventive" reasons.

A better practice is to culture the skin, blood, urine or other tissue to confirm an infection and pinpoint the type of bacteria causing it. That allows the most appropriate antibiotic to be prescribed.

"If we see a big, infected wound or if we have a dog with pneumonia, we can culture that, find out what the bug is and what antibiotic will specifically target it, as opposed to using an overly broad-spectrum antibiotic that isn't needed," Johnson says.

But cultures can be expensive, and not everyone can pay for it.

That leaves veterinarians guessing at the best way to proceed.

What's the answer? The World Health Organization and other institutions say use the drugs only in cases with a definite diagnosis, ruling out viral and fungal infections, parasites and other conditions that don't respond to antimicrobial therapies.

For instance, antimicrobials aren't indicated for viral upper respiratory infections such as feline herpesvirus or canine influenza unless they are accompanied by secondary bacterial infections. Most cases of feline lower urinary tract disease don't involve bacterial infection. Treatments such as a change in diet or stress relief techniques are more effective. And some wounds may simply require cleaning with a topical antiseptic solution.

"If your dog or cat or child is not in pain and it's not life-threatening, let their body deal with it, whatever it is," Johnson says. "Antibiotics are a very powerful tool, and they save lives, so you don't want to not use them when necessary, but the main thing to understand is that they are not a cure-all."