Antibiotics: How Long Is Long Enough?

The arsenal of antibiotics strong enough to squelch nasty bacteria is rapidly dwindling worldwide, which makes worried infectious-disease doctors more intent than ever that the drugs be deployed only when strictly needed.

These specialists know that every antibiotic carries its own risks, and that the more frequently and broadly a drug is used, the more likely it is that harmful microbes will develop tricks to sidestep it. But a team of researchers in the Netherlands, where a more selective use of antibiotics has led to much lower levels of resistant bacteria than are circulating in the United States, thinks the medical finger-waggers have not gone far enough.

“As doctors, we’ve paid a lot of attention to questions of which antibiotics we should use to treat what sorts of infections, but have focused much less on how long that treatment should last,” said Dr. Jan Prins of the Academic Medical Center in Amsterdam.

In a small but provocative study published in the June 10 issue of the British medical journal BMJ, Dr. Prins and colleagues from nine hospitals suggested that even some cases of pneumonia — a potentially life-threatening disease — could be treated with a three-day course of antibiotics, rather than the conventional 7- to 10-day treatment.

Continue reading the main story

The Dutch study analyzed the cure rates of 186 adults who had been hospitalized with mild to moderately severe pneumonia. All received three days of intravenous amoxicillin to start. After that, the 119 who were showing substantial improvement were randomly divided into two groups; about half continued with another five-day course of oral amoxicillin, and the others got look-alike sugar pills. Neither the patients nor the doctors knew who was getting which treatment until the end of their participation in the study.

By the end of treatment, roughly 89 percent of the patients in each group were cured of their lung infections without further intervention. In a commentary accompanying the study, Dr. John Paul, a microbiologist at Sussex County Hospital in Brighton, England, writes that, at least for a subset of patients with uncomplicated, community-acquired pneumonia, the finding “suggests that current guidelines recommending 7-10 days should be revised.”

As lead investigator of the Dutch study, Dr. Prins was not ready to go quite that far. He cited the study’s small size and the seriousness of the illness as a reason to wait until the finding is independently replicated before advising a wholesale change in practice.

“This is just the first paper, but I do hope others will have the courage to test this,” Dr. Prins said.

Treatment decisions, he added, should be guided by science, not tradition.

Dr. Michael Fine, a pneumonia expert at the University of Pittsburgh, said he agreed with Dr. Prins that American doctors should cut back on their use of antibiotics, particularly against many respiratory infections, which are either caused by a virus or would get better on their own without treatment. “But I wouldn’t start with pneumonia, where the risk of undertreatment is so great,” Dr. Fine said. “In terms of drug resistance, we have much bigger fish to fry.”

In the United States, amoxicillin is not even the antibiotic of choice in treating pneumonia, Dr. Fine said, partly because, unlike in the Netherlands, overuse of penicillins and other broad spectrum antibiotics for acute bronchitis, earaches, clogged sinuses, sore throats and colds has caused widespread resistance in the organisms that cause pneumonia.

Doctors in the United States often cite pressure from patients as the reason for prescribing an antibiotic “just in case” when the source of an upper respiratory infection cannot be precisely determined. But Dr. Prins said doctors in the Netherlands rarely treat sore throats or acute bronchitis with antibiotics, and their patients seem to accept that — maybe because of the language doctors use to describe the infection. “We’re more likely to call it a bad cold or the flu, and send them home to rest and drink lots of fluid,” he said.

The results of a 2002 study comparing antibiotic use by Dutch and Belgian doctors in two similar communities bears out the point. Symptoms that Belgian family practitioners labeled bronchitis, the Dutch doctors called flu or common colds. The Belgian doctors were also much more likely to prescribe antibiotics.

“My idea in treatment of pneumonia and anything else is that I’d like to use as much antibiotic as needed, but no more,” Dr. Prins said.

For a particular patient, the risks of undertreating should always be taken into account, he said, “but in the end, consumption of antibiotics determines resistance rate, and as an individual and as a community, you’re going to be worse off if one day there are no more good antibiotics to treat your condition.”

Dr. Ralph Gonzales, an internist at the University of California, San Francisco, was recently on a panel commissioned by the Centers for Disease Control and Prevention to develop evidence-based guidelines for the appropriate use of antibiotics for various illnesses. In their review of the science, Dr. Gonzales said, the panel found that the evidence for how long a drug needs to be given varies markedly from illness to illness.

For some ailments — simple urinary tract infections, for example — substantial research shows that a short course of the right antibiotic works as well as longer treatments, at least in women under 60. In other ailments, like acute bronchitis, the best research suggests that antibiotics are almost never warranted, because the infection is viral, or in other ways self-limiting; the drugs do not speed recovery. In still other cases, like acute sinusitis and sore throats, for example, antibiotics will definitely help a small fraction of patients, Dr. Gonzales said. The trick is to figure out which ones.

“There’s good evidence that a 10-day treatment with penicillin will stop strep throat,” Dr. Gonzales said, “whereas if you stop the drug after three days or five days, the patient will tend to relapse. But strep throat only accounts for about 10 percent of all the sore throats that walk in the door of the clinic.”

The leading indicators that an infection might be strep are a sudden onset of a sore, red throat dotted with white patches, fever and swollen lymph glands, but no cough or nasal congestion. It is the doctor’s job, Dr. Gonzales said, to be hard-nosed in evaluating the symptoms and perhaps running a laboratory test to ensure that only those patients with strep get the drug.

Patients should never assume they can safely taper treatment on their own when they start to feel better, Dr. Gonzalez said. They not only risk strengthening the bad bug and suffering a relapse if the incomplete drug dose knocks the bacteria down but not out, but they also contribute to the problem of drug-resistant microbes setting up shop in their own families and community.

“It can be confusing for patients, but both undertreatment and overuse of antibiotics promote drug resistance,” Dr. Gonzales said. “Undertreatment is the match, but overuse is the gasoline poured on the fire.”