HIV and ID Observations

With the news that a generic form of levofloxacin has just been approved by the FDA, some thoughts about this remarkable antibiotic:

1. When it was first approved in 1996, levofloxacin was the first oral antibiotic that really covered all common causes of community acquired pneumonia. Strep pneumo, H flu, mycoplasma, legionella, chlamydia — check, check, check, check, and check. Doctors realized this, of course, and prescribed it like mad.
2. Grave prognostications about the threat of pneumococcal resistance to quinolones invariably followed — but this never materialized to a sufficient degree to change practice, at least not in the United States. It has remained unusual to find one of these levofloxacin-resistant pneumococci in clinical isolates, and surveillance reports show that such resistance is surprisingly rare.
3. However, rates of gram negative (especially) and Staph aureus resistance to quinolones just keep going up and up. Amazing, these bugs are smarter than we are! What a concept!  These UTI guidelines cite “collateral damage” of using quinolones for uncomplicated cystitis — a wise move.
4. These cautionary notes notwithstanding, some medical services think it’s mandatory that every patient receive at least one dose of levofloxacin prior to hospital discharge. I made that up, and have mentioned it before, but you get my point — this is still one popular antibiotic. See #1, above.
5. As numerous other quinolones fell by the wayside due to safety issues, levofloxacin has remained overall quite safe. Temafloxacin, trovafloxacin, grepafloxacin, sparfloxacin, gatifloxacin — gone, but not forgotten. Trivia question for detail-obsessed ID types (which means all of us):  Why were each of these pulled off the market?  And what were their trade names?  (Hint: several of the trade names sounded like they were lifted right from a science fiction novel.*)
6. But even though it’s relatively safe, levofloxacin does have some serious side effects. Probably the worst of these  is the tendon rupture/tendinitis issue — deserving of the dreaded “black box” —  but I’ve also seen anaphylaxis, delerium, QT prolongation, photosensitivity, and many many cases of C diff. Bottom line is that this is a drug: we humans did not evolve to have levofloxacin coursing through our system.  (Tell that to cardiologists about statins.)
7. In vitro, levofloxacin is neither the most active gram-negative or gram positive quinolone. Those would be ciprofloxacin and moxifloxacin, respectively.  But it hasn’t really seemed to matter much, has it? See #1 (again), above.
8. Presumably, the availability of generic levofloxacin will eventually eliminate the levofloxacin to moxifloxacin swap often mandated by payors. Since our hospital has levofloxacin as its preferred respiratory quinolone, it has set up the peculiar practice of using levofloxacin during the hospitalization, then changing to moxifloxacin on discharge. This can’t make medical sense — they are not identical after all —  so I for one will be glad to see this exchange come to an end.

*An experienced starship pilot, Raxar expertly navigated his Tequin-400 aircraft through the high mountains of Trovan. This was no easy task, as the planet’s distinctive craggy peaks were nearly completely obscured by thick clouds of Omniflox — the highly-toxic gas released from volcanic eruptions. Off in the distance, he could see the bright lights of the capital city Zagam.  “Home at last,” he said out loud.  But Raxar spoke too soon, for little did he know that this final leg of his journey would take him to worlds unknown …