Antimicrobials: When 'Short Courses' Are Enough

Matthew F. Watto, MD; Paul N. Williams, MD


November 03, 2021

This transcript has been edited for clarity.

Matthew F. Watto, MD: Hello, Curbsiders. We're going to be talking about some antibiotic pearls today. Paul, would you tell them about our great guest and who we will be trying to channel on this video?

Paul N. Williams, MD: These pearls are culled from our podcast on antibiotics with the incredibly thoughtful and well-spoken Dr Adi Shah, who somehow managed to distill down how to prescribe antibiotics — a gigantic topic that people do fellowships for — into a 45-minute episode; really super-helpful stuff. Why don't we get right into it? He started off with a helpful framework that incorporates antimicrobial stewardship, but basically how he thinks about prescribing antimicrobials in general.

Watto: I love his framework. Before I prescribe anything, I ask myself a series of questions. The first question is, is this infectious or not infectious? It just makes sense to ask this first question, because we may forget to consider other possibilities, such as serotonin syndrome, DVT, malignancy, or drug adverse effects.

Many other things can cause a fever that aren't infectious. So first, can you convince yourself that this person actually has an infection? Then you think about other things: What has been their previous antibiotic exposure? What site do I think is infected? What kind of bugs am I going to need to cover based on that site? Do I need to order any testing before I start antibiotics? And then do I need source control? I know you have another favorite question, Paul: What's worked in the past?

What else struck you from this whirlwind tour of antibiotics?

Williams: It was another general principle and a way to look at antimicrobials in general. The ACP practice advisory indicates shorter durations for antimicrobial prescribing based on a lot of relatively recent data. We are going shorter and shorter. In our salad days, we prescribed 14 days of antibiotics for pretty much everything.

Watto: Quinolones for COPD exacerbation.

Williams: Community-acquired pneumonia, that was maybe kind of iffy; we would treat forever and do serial x-rays — just bananas.

But it turns out that we actually have evidence and data to guide us now as opposed to just doing what feels right within the lunar calendar.

For conditions such as acute bronchitis, 5 days of therapy are probably enough. For community-acquired pneumonia in immunocompetent adults, 5 days may well be enough. For uncomplicated cystitis, anywhere between 3 and 5 days, depending on what agent you choose. Even for uncomplicated pyelonephritis, if the patient is doing okay, you can give a relatively short course — 5-7 days — with fluoroquinolones and maybe a little bit longer for trimethoprim-sulfamethoxazole, but that's up for a bit of debate. Nonpurulent cellulitis is also a 5- to 6-day course.

In general, longer antibiotic courses may not be necessary, and the current trend is to shorten the duration of therapy. You need a good follow-up plan to ensure that patients are responding clinically. It's not a "set it and forget it" approach.

Watto: We trained in the "longer is better" era: Give the longest course of the strongest agent available.

Williams: Just sterilize everything.

Watto: Obviously, we have done some harm with that because there are all these resistant bugs now. Our great friend, Dr Boghuma Titanji, told us that sometimes when she's treating something like a cellulitis, she'll prescribe a range, such as 5-7 days, and she follows up with patients, either by phone or with a wound check during that time period. She may adjust the course of antibiotics, but she's given them that 5- to 7-day course. That way, she has a little bit of flexibility built into it, and she doesn't have to send another prescription if she wants to extend it a little bit. I love these two points, that you can prescribe a range and you should be checking in with the patient during that time.

The quicker the patient gets better from the infection, the more you can shorten some of these courses, especially for less complicated infections. Again, I can't say enough that we are not talking about the critically ill patient who is hospitalized in the ICU. These are mostly ambulatory outpatients that we're talking about here.

The trigger with fluoroquinolones was pulled so frequently that there's a great deal of resistance to them now. Our guest said he likes those agents when he needs them because they achieve really great blood levels. And they cover a nice therapeutic range. But we want to save those agents for when we really need them.

Williams: With the black box warning on fluoroquinolones about the neuropsychiatric effects, the musculoskeletal effects, the Q-T prolongation, and the other hazards, your patient had better really need them if you prescribe them. Sometimes they are warranted, but if not, find something else to use.

Watto: The last point I wanted to bring up is that just because patients are hospitalized, it doesn't mean that they necessarily need IV medications. There is a list of antibiotics with good oral bioavailability, and when given them by mouth, they do almost just as well as they would given intravenously. Some of those include trimethoprim-sulfamethoxazole, metronidazole, doxycycline, fluoroquinolones, and your old favorite, clindamycin. Paul Sax has a list on his HIV and ID Observations blog.

Many antibiotics, when given IV, require a significant amount of fluid. Patients with heart failure, for example, tend to retain fluid, so we don't want to give excess fluid. Some IV antibiotic preparations include as much as 500 mL of normal saline. So once the patient has turned the corner and is stable, think about switching to an oral preparation. Any other points, Paul, before we end?

Williams: No, I think our viewers can now prescribe almost any antibiotic and feel great about it.

Watto: With a 3-minute video!

Williams: If you would like a deeper dive on this topic, I encourage you to listen to the full podcast, An Antibiotics Primer, with @IDdocAdi. Until next time, I'm Dr Paul Nelson Williams.

Watto: And I'm Dr Matthew Frank Watto. Thank you and goodbye.

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