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Duration of Antibiotic Treatment

“Take this medicine for 10 days for your child’s ear infection” 

“Do not miss a dose of this 7 day antibiotic course”

“Just 3 days of this antibiotic will get rid of your infection”

Most of us are good guys and rule followers, right? Especially about our health. If the clinician we trust tells us that we need to take medicine for a set number of days, we do it, even if we feel better after the first 48 hours. A #smartmomma asked me recently to dig deeper into this topic a little bit as it relates to antibiotic medicine, to help understand why it might truly be worth it to chase your kid around the house twice a day, hold her down, and do whatever other wrestling moves need to be done to get that horrible antibiotic down yet again. For 6 more days! (Been there)

I’m happy to report straight out of the gate that duration of antimicrobial therapy is indeed guided by science.

There’s a lot of very interesting math that involves logarithms (wut the wut) in pharmacology (the study of drugs), whereby in the lab intricate models are developed of timelines and dosages required for certain antibiotic medicines to kill or render ineffective different types of germs. After this data has been accumulated and analyzed animal models are sometimes used to further refine the research and then recommendations in humans are developed. The FDA has oversight of this process.

In recent years there has been plenty written in the lay press and the scientific literature on the emergence of “superbugs” which are immune to any and every antibiotic and the resultant dangers of antibiotic resistance. I’ve written before about antibiotic stewardship, and this is a real concern. Hand in hand with this concept necessarily comes the question of duration of antibiotic therapy for certain conditions, and in fact practice has changed for some illnesses after solid research. For example, when I first started in medicine strep throat was treated with penicillin or amoxicillin by mouth 3 to 4 times a day, and now it’s been shown to be effectively treated with just ONCE daily dosing. Similar advances have been made with infections such as the simple urinary tract infection: now antibiotics are given for just 3 days total with effective tests of cure (when the urine is sent to the lab for culture after the treatment and the infection is shown to be gone), instead of the full week of antibiotics as required previously.

doctors hand looking at petri dish

So if we have a few situations where fewer days and lesser doses of antimicrobial medicines are appropriate, why can’t we generalize and say that people can and should stop taking their antibiotics once they start feeling better?

That notion has been put forward by a few scientists, with mixed reviews. Here are a few general concepts behind the theory that over-treatment rather than undertreatment should be our biggest concern:

  1. Some scientist claim that failing to complete a course of antibiotics hasn’t contributed to antibiotic resistance, so perhaps in fact we all SHOULD shorten our antibiotic duration to just the point where we feel better. This was written as an analysis in the British Medical Journal last summer and it got quite a bit of press coverage. The authors analyzed published research and noted that little data exists that suggests that shorter courses leads to treatment failures or antibiotic resistance. However, they note that some solid data suggests that shorter treatment can compromise overall recovery in some situations.
  2. One size doesn’t fit all. Or, in other words, having a fixed number of days of treatment for every patient might not account for individual differences in response to therapy, and this very topic is hard to study. Structuring research around this subject is difficult to do with rigor that could produce generalizable results.

Critics of the “stop the medicine when you feel better” approach agree that there is insufficient data with which to draw conclusions either way, so that for now we should stick with affirmed laboratory science that involves pharmacokinetics (the properties of how drugs are metabolized), which is how the standard durations were obtained in the first place.

I love micro biology

Recently, I asked an academic doctor of pharmacy (PharmD) what she thought of the idea of not taking a full course of antibiotics. She brought up many confounders that should be taken into consideration, such as location of infection in the body (some areas are more difficult to penetrate than others), the way the medicine is dosed, and the possibility of the presence of other co-infecting organisms. Her data based recommendation was NOT to stop a course early for now until more evidence exists that support doing so, even though the idea sounds plausible and nice. Since I’m a gal who goes with the evidence, understanding that science doesn’t care whether or not you like it, I’m inclined to agree with her.

What I DO think you should do is the following:

  1. Ask your clinician if the antibiotic medicine being prescribed is the best (not necessarily strongest) one that will work against the BACTERIAL infection at issue. First and foremost, no antibiotic should be given for any viral infection.
  2. The antibiotic should adequately target the infection, but bear in mind that you don’t need a high order medicine to get rid of what a more entry-level one would do just as well.
  3. Have a conversation about the duration of therapy: asking why 14 days are prescribed instead of 10 is a reasonable question.

This is a very interesting topic that will certainly get more attention as patterns of antibiotic resistance and “superbugs” continue to emerge. What I hope is that more doctors, patients, and public health officials will be responsive in the calls to action to do more research, participate in more research, evaluate more research, and implement that research so that we can do what’s best to give the optimal course of medicine in a given situation.

Back to chasing kids for the time being.