Most medical guidelines do not recommend using antibiotics for respiratory tract infections with a runny nose -- advice based on a study that found antibiotics to be totally ineffective for the condition -- but doctors tend to prescribe them anyway.
The New Zealand study, published online at the British Medical Journal's website BMJ.com, analyzed seven double-blind, placebo-controlled, randomized trials and found that antibiotics can sometimes be effective when used on acute purulent rhinitis (a runny nose with colored discharge). The drawback is that the drugs were only beneficial for one out of every six patients.
Furthermore, the harmful side effects of the medicine, including diarrhea, vomiting, rashes, hyperactivity and abdominal pain, affected at worst one out of 12 patients, and at best one out of 78 patients. The placebo group in all trials recovered from their condition with no problems. This leads the authors to believe that, while antibiotics can sometimes be effective in treating a runny nose, most patients will recover without them, avoiding possibly harmful side effects.
Antibiotics should only be used as a last line of defense in acute purulent rhinitis, when the symptoms have lasted long enough to cause patients concern, the study concluded.