When sore throats and sniffles from a cold take a toll, many people’s first reaction is to ask a doctor for an antibiotic. But do antibiotics really counteract common colds and viruses?

Numerous studies have shown that antibiotics provide little relief for cold and flu sufferers. What’s more, when prescribed inappropriately, they may actually be harmful to your health.

Origins

Antibiotics fight bacterial, fungal, or parasitic infections. Since the antibiotic penicillin was discovered in 1928, antibiotics have developed as important treatments for a number of conditions. These include strep throat, bacterial pneumonia, and wound infections, among many others.

However, common colds aren’t caused by bacteria, fungi, or parasites -- viral pathogens are to blame. It’s a simple distinction, but it hasn’t stopped countless physicians from prescribing antibiotics to cold sufferers.

Granted, many physicians prescribe antibiotics to safeguard against a possible bacterial infection or other complication. But studies have shown that such precautions are only justified for certain types of patients, such as the elderly or patients with high fevers.

“I would say the majority of my patients come in thinking they need an antibiotic,” says Scott Joy, MD, chief of clinical services with Duke’s Division of General Internal Medicine. “The default has always been, ‘I’ll just take an antibiotic and I’ll get better.’ Well, they were going to get better because they just needed to give it another three days. It wasn’t the antibiotic that did it.”

Inappropriate antibiotic prescriptions have become less common in recent years, but 50 percent of antibiotic prescriptions are still unnecessary, according to a 2006 study in the journal American Family Medicine. Some studies put that percentage even higher, but the bottom line is this: antibiotics are too often prescribed for common symptoms -- like sore throats, coughing, and sinus congestion -- that they can’t cure.

Click play to hear Joy discuss why patients might think they need antibiotics -- and why they’re usually wrong:

Potential Harm

Not only are antibiotics often unnecessary, they could even make you sicker. Overprescribing can be damaging in two main ways:

• Causing side effects, allergic reactions, or other health problems
• Perpetuating drug-resistant bacteria that are harder for medicines to extinguish in the future

Like any drugs, antibiotics can have side effects. Upset stomach and diarrhea are among the most common. But side effects from antibiotics can be significantly more severe, even life-threatening. They can range from yeast infections to organ dysfunction and anaphylactic shock.

While such side effects are by no means widespread, Joy cautions that even a slight risk of harm should be enough to give physicians pause. “There are a fair number of patients who in their first exposure to penicillin will have an anaphylactic reaction with potential death,” Joy says. “So these drugs should not be taken lightly.”

Aside from negative effects on individuals who take antibiotics, overuse or misuse can also lead to antibiotic resistance in bacteria. This can occur when the antibiotic is only able to kill some, but not all, of the targeted bacteria present in the body. The bacteria that survive can develop resistance to the effects of the antibiotic, and they can reproduce and make infections very challenging to treat in the future.

For example, Staphylococcus aureus, one of the bacteria that can cause staph infections, has notoriously developed resistance to penicillin and several other types of antibiotics over the years, making treatment difficult.

While antibiotic overuse isn’t the only reason for resistance problems, taking antibiotics only when necessary helps curb the development of drug-resistant bacteria.

“Giving an antibiotic inappropriately leads to tougher bugs to treat down the road,” Joy says. “So as a clinician, you’re much better off spending the time explaining to patients with colds, ‘You’re going to have these symptoms five to seven days. I can make you feel a little better with a cough suppressant, but antibiotics are going to do no good and potentially do some harm.’”

Click play to hear Joy explain other ways in which inappropriate antibiotic prescription can be harmful to patients: