Lower respiratory tract infections, including acute bronchitis , are among the most common conditions treated in primary care. Although most lower respiratory tract infections are caused by viruses, which do not respond to antibiotics, many people with these infections receive antibiotic prescriptions anyway.

According to some research, physicians inappropriately prescribe tens of millions of antibiotics each year for viral infections. Antibiotics are expensive, generally costing $50 to $100, and are not without their risks. While serious complications are rare, a more troubling concern is the growing problem of antibiotic resistance.

Overexposing bacteria to antibiotics causes them to become resistant, eventually making some antibiotics ineffective against them. Because of this, some infections that should be easily treated, now require extended hospital stays and more expensive and toxic medications.

Proponents of antibiotic treatment for lower respiratory infections contend that is it efficient, satisfies patients, and may prevent the inevitable onset of bacterial infections in some cases. A new study in the June 22/29 2005 issue of the Journal of the American Medical Association found that immediately treating lower respiratory tract infections with antibiotics was associated with little benefit, compared to using no antibiotics or delaying antibiotic treatment.

About the Study

This study included 640 participants aged three and older who visited one of 37 physicians in England due to a cough lasting three weeks or less, and at least one other lower respiratory symptom (i.e., phlegm production, chest pain, shortness of breath, or wheezing). People with asthma or possible pneumonia were excluded.

The participants were randomly assigned to receive immediate antibiotic treatment, no offer of antibiotics, or delayed antibiotic treatment. The participants who received delayed treatment were told they could request a course of antibiotics if their symptoms did not resolve within 14 days.

The participants kept a daily log of their symptoms, satisfaction with treatment, and belief in the effectiveness of antibiotics.

The Findings

The participants’ coughs lasted an average of 10 days before visiting the physician, and an additional 12 days following the visit. One person who was not offered antibiotics developed pneumonia , which was successfully treated.

Prescribing either immediate or delayed antibiotics did not alter the duration or severity of the cough, compared to no offer of antibiotics. Antibiotics did, however, reduce the duration of “moderately bad symptoms” by one day.

Participants who received immediate antibiotics were slightly more likely to be very satisfied with their treatment and believe in the effectiveness of antibiotics.

These findings are limited by the fact that there was no comparison group that received placebo medications. This may have caused the antibiotics to appear more beneficial, due to a “placebo effect,” in which the participants’ symptoms improved because they were aware they were taking medication.

How Does This Affect You?

These results suggest that immediate antibiotic treatment has little benefit in people with lower respiratory tract infections. The modest benefit of reducing the duration of moderately bad symptoms by one day is unlikely to outweigh the potential harms caused by the inappropriate use of antibiotics, namely antibiotic resistance.

While participants who received antibiotics were more satisfied, they were also more likely to believe in the effectiveness of antibiotics. This may “train” patients’ to expect antibiotics, thereby encouraging physicians to prescribe more antibiotics—all potentially contributing to increased antibiotic resistance. This study supports the view that physicians should avoid giving antibiotic prescriptions for suspected viral respiratory infections, and instead take the time to explain why antibiotic treatment may be more harmful than beneficial.

This is not to say, however, that no lower respiratory infections should be treated with antibiotics. These infections may occasionally develop into pneumonia, especially in patients with chronic respiratory conditions or other serious health problems. The challenge for researchers is to find out how to identify and treat otherwise healthy patients who are at most likely to benefit from prompt antibiotic coverage.