ID Learning Unit — Choosing a Quinolone
Paul Sax • June 24th, 2012
We love quinolones on medical services, and it’s easy to understand why. Advantages:
- Ideal spectrum for several common infections, including community-acquired pneumonia, UTIs, and more complex infections when combined with other drugs
- Great oral absorption
- Few drug-drug interactions
- Once- or twice-daily dosing
- Generally well tolerated
- Reasonable cost
But how do you choose between them? Below, in a concise and admittedly somewhat oversimplified table, is all the medical intern/resident/hospitalist needs to know about our friends the quinolones:
||Activity vs gram – rods (rank)
||Activity vs gram + cocci (rank)
||Activity vs Anaerobes (rank)
||Don’t use for Strep pneumo; no association with increased cardiac death in recent study (unlike levo, azithro)
||Active (left) enantomer of ofloxacin – hence its name. How cool is that?
||Not active vs. Pseudomonas; generally the preferred quinolone for mycobacterial infections
But it’s not all sunshine and happiness with these drugs. Problems:
- That nasty tendon issue
- Can make people (especially the elderly) kind of crazy – “like 5 cups of Starbucks, and not in a good way”, was one patient’s memorable description
- QT prolongation
- Oral absorption blocked by concomitant iron, magnesium, calcium, aluminum, and probably also Krugerrands if you happen to be eating them
- C diff risk, something we really didn’t see until the emergence of the more virulent strain
- Ever rising rates of resistance with gram negative rods, Staph aureus
Bottom line? These are great antibiotics – but they are not interchangeable, and not 100% safe.
Extra credit: Can you name the five quinolones that have been pulled by the FDA for safety reasons? Double points if you get the reason they are no longer available, triple points if you also get the brand names and match them to the actual drugs.
Here’s a hint to get you started.