Are Doctors Wrong About Finishing Your Antibiotics?

As we edge closer to our worst-case scenario, an important study may point to a simple solution that goes against everything doctors have been telling you.

Scientists have long offered several solutions to the rise of antibiotic-resistant bacterial infections, but this one will surprise you: Don’t finish your treatment course.

The antibiotic era began in the mid-1930s with the development of sulfa drugs and leaped forward in the early 1940s with the mass production of penicillin. Since then, scientists have developed a wide variety of types of antibiotics. Nonetheless, with their overuse, many strains of bacteria have become resistant. Methicillin-resistant Staphylococcus aureus (MRSA) and extended spectrum ß-lactamase producing and carbapenem-resistant opportunistic bacteria have become increasingly problematic. Occasionally, patients get infected with bacteria resistant to all commercially available antibiotics. In other words, we’ve taken our first steps into the post-antibiotic era.

The best way to reduce the problem of resistant bacteria is to refrain from giving antibiotics to patients who don’t need them. Many prescriptions are written for symptoms such as cough, runny nose, and congestion—infections that are often caused by viruses for which antibiotics are useless. The all-to-easy-to-remember Z-pack (azithromycin) is a prime offender.

Viruses can also cause pneumonia and sore throats. Because bacteria can also cause these diseases, doctors should make every effort to determine whether these infections are actually caused by bacteria before writing a prescription. For example, rapid diagnostic tests can distinguish viral throat infections from strep throats and chest X-rays can distinguish viral pneumonias from bacterial pneumonias.

Another important factor in preventing antibiotic resistance is vaccination, especially with the pneumococcal and influenza vaccines. Although influenza is a virus, influenza pneumonia can make the body predisposed to bacterial pneumonias caused by pneumococcus and staph. It’s much easier to avoid antibiotics if patients aren’t infected in the first place.

One factor working against doctors in reducing the problem of antibiotic resistance is history. For decades, doctors and patients have believed that finishing the prescribed course of antibiotics can help prevent the development of antibiotic resistance, even though little evidence is available to support this claim. On the other hand, abundant evidence supports the fact that prolonged use of antibiotics promotes bacterial resistance.

The dictum that it is important to finish the antibiotic course is persistent and ingrained. During Antibiotic Awareness Week in 2016, the World Health Organization advised patients to “always complete the full prescription, even if you feel better, because stopping antibiotics early promotes the growth of drug-resistant bacteria.” Similar advice has appeared in national campaigns in Australia, Canada, Europe, and the United States. Indeed, in the United Kingdom, this advice is included in high-school curricula.

Although these studies aren’t easily performed, investigators are now starting to look at shorter treatment courses. For example, bacterial infections of the kidneys (pyelonephritis) have historically been treated for 14 days. Recently, two studies found that five days or seven days of treatment could be just as effective. It is likely that these findings could be extended to infections like sinusitis or cellulitis.

Probably the most interesting recent study involved patients with community-acquired bacterial pneumonia. Five days into antibiotic therapy, patients were randomized into two groups. In one group, antibiotics were stopped if the patient’s temperature had returned to normal. The other group continued antibiotics as determined by the physician. The outcome was the same in both groups. Stopping antibiotics once the fever had abated was good enough.

This study makes sense. When bacteria like pneumococcus infect the lungs, they reproduce themselves. But it’s not the bacteria that cause the symptoms of cough, fever, and difficulty breathing; it’s the immune system—specifically, white blood cells flooding into the lungs. The inflammation seen on chest X-rays is evidence of this immune response. When the immune system, in conjunction with antibiotics, has done its job, the signs and symptoms of inflammation, such as fever, abate. At this point it’s fair to say that bacterial replication is no longer part of the process. The only effect of antibiotics turns to promoting resistance, especially for bacteria that live on the lining of the intestine (i.e., opportunistic bacteria that comprise the so-called microbiome).

Further, the length of antibiotic courses has always been somewhat arbitrary, usually involving multiples of five or seven—presumably because we have five fingers on each hand and there are seven days in a week. But bacteria don’t replicate based on the metric system or fractions of the lunar month. It would make much more sense to determine an antibiotic course based on the patient’s response, rather than on an arbitrary length of time determined at the beginning of the illness. Especially because all patients are different and respond differently to their infections. Although it might feel wrong to treat a bacterial pneumonia with 6.5 days of antibiotics, for some patients that would be the right thing to do.

The lesson from these studies is that for many infections patients should be encouraged to stop antibiotics as soon as they feel better. This will help to reduce the enormous overuse of antibiotics that has caused bacteria to become progressively more resistant to the only weapon we have to kill them.

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Paul A. Offit is a professor of pediatrics and director of the Vaccine Education Center at the Children’s Hospital of Philadelphia. He is the author of Pandora’s Lab: Seven Stories of Science Gone Wrong.