Amoxicillin is one of the most popular moderate-spectrum, bacteriolytic antibiotics on the planet. It is the "go to" drug of choice when treating common skin infections, urinary tract infections, salmonella, Lyme disease, pneumonia, and Chlamydia. It is also commonly prescribed for bacterial sinusitis (which in many cases is caused by viruses, and thus unaffected by amoxicillin or any antibiotic), and for a host of other respiratory infections.
According to a new study published in the respected British journal The Lancet, however, amoxicillin performs no better than a placebo at treating the symptoms of lower respiratory tract infections, and doesn't prevent these symptoms from getting worse.
The British scientists followed the treatment of over 2,000 patients with lower respiratory tract infections. 1,038 of these patients were treated with amoxicillin three times a day for seven days, while 1,023 of the patients were "treated" on the same schedule with a placebo. All patients were over the age of 18, and all had suffered from a cough for fewer than 28 days, but none were ever diagnosed as having pneumonia. The researchers assessed all of the subjects' symptoms at the start and at the completion of the study, and the subjects themselves kept detailed diaries of their symptoms, recording things like the severity of their coughing, chest pains and muscle aches, shortness of breath or wheezing, blocked or runny noses, fever, etc., rating each symptom for severity on a scale that ranged from "no problem" to "as bad as it could be."
At the end of the 7-day study, the researchers had found little to no difference in the two groups in either the severity or duration of their symptoms. Even among subjects over the age of 60, the amoxicillin seemed to have no more effect than the placebo. Symptoms rated "worse" or "moderately bad" by the subjects lasted an average of six days in the amoxicillin group and seven days in the placebo group.
In another interesting finding, the subjects who took amoxicillin experienced far more negative side effects (such as diarrhea, nausea, and rashes) than the placebo group – 29% in the amoxicillin group and 14% in the placebo group. Researcher Paul Little, from the University of Southampton, said of the findings, "Our results show that most people get better on their own. Using amoxicillin to treat respiratory infections in patients not suspected of having pneumonia is not likely to help and could be harmful."
Not just ineffective, amoxicillin could also possibly be detrimental
The researchers also concluded as a result of their findings that the overuse of amoxicillin might be contributing to the development of antibiotic-resistant bacteria. The study's general finding was that "Amoxicillin provides little symptomatic benefit for patients presenting in primary care who are judged to have clinically uncomplicated lower-respiratory-tract infections … any mild, short-term benefits of antibiotic treatment should be balanced against the risks of side effects and, in the long-term, of fostering resistance."
So if you wind up with a persistent cough or lower respiratory infection this winter, and your doctors hand you a prescription for amoxicillin, you might want to show them this article or refer them to the original study in The Lancet. At a cost of $4 to $17 for a 30-day supply of amoxicillin, you might be better served by asking your doctors to prescribe you a placebo, because the research seems to indicate that the placebo will work just as well, and without as much risk of side effects.