Barbara Wells Trautner, MD, PhD, discusses why physicians are using fluoroquinolones despite the FDA’s warning.
Barbara Wells Trautner, MD, PhD, associate professor, director of clinical research, Baylor College of Medicine, discusses why physicians are using fluoroquinolones despite the FDA’s warning.
Interview transcript (slightly modified for readability):
"We’re exploring this in an outpatient setting, as part of my interest in outpatient stewardship for UTI, and we’re going around asking providers in primary care why they are using fluoroquinolones. I think the leading concern is we’re hearing a lot of resistance in E coli to Bactrim. So, if you read the IDSA UTI guidelines, which are a couple years old now, they give your 3 first-line drugs as Bactrim, nitrofurantoin, and fosfomycin.
Right after Bactrim, they say your resistance on your local antibiogram needs to be less than 20% if you’re going to use Bactrim as a first choice. Most people don’t have an outpatient antibiogram and hearing that resistance to Bactrim means people aren’t using that as their first-line drug.
A couple [physicians] told me, I’ll use Bactrim if someone’s not really sick, but if they come in and they’re diabetic or falling apart, I just have to use a fluoroquinolone because I don’t want them to get worse. What’s interesting though is we’re starting to build an outpatient antibiogram specific to UTI but the data we have from the outpatient setting in general shows that in Houston in our public health system and the VA hospital, E coli resistance to fluoroquinolones varies between 30% and 40%. So, actually quinolones may be worse than Bactrim in our setting in terms of resistance.
I also think resistance is perpetuated by the fact the guidelines say don’t use Bactrim if there’s resistance; but, they don’t mention it for any other drug. Now with nitrofurantoin, there is a lot of concern since it doesn’t reach plasma or tissue levels. If someone has impaired renal functions, it’s not really getting into the urine, so it wouldn’t be working. That’s been refuted by several publications, but that idea is definitely out there, and older patients without creatinine clearance should not get nitrofurantoin.
With fosfomycin, we just don’t see it used at all and we’ve asked people why. First of all, it’s not on the formularies for a lot of places. [Furthermore,] you have to call for ID approval and it does not have standardized resistance tests that can go in the typical resistance panels that are automated in the labs. To do the resistance testing, you’d have to request it, and it’d have to be a specific disk test. Since it’s not appearing on the list of antibiotics the organism is susceptible to, people are not choosing fosfomycin.
I do think it really relates to the fact that quinolones do have a good reputation. I reach for them often because when the organism is susceptible, they work, and they work fast. Now, though, I don’t reach for them as often because I have a really good understanding of the side effects. The tendon rupture has been known for years, and now there’s also the concern for dysglycemia. There are also more and more concern about neuropathies causing delirium, and QT prolongation with arrhythmias, and now, adding aortic aneurysm to the list, potentially, I’m really worried about using them."