Fluroquinolones - SOA Flashcards
List the FQs:
- ciprofloxacin
- levofloxacin
- moxifloxacin
- delafloxacin
What is the mechanism of action of the FQs?
ciprofloxacin, levofloxacin, moxifloxacin, delafloxacin
- FQs inhibit DNA synthesis by inhibiting bacterial topoisomerases
- target DNA gyrase (topo II) in GN
- target topo IV in GP
What are the mechanisms of resistance to FQs?
ciprofloxacin, levofloxacin, moxifloxacin, delafloxacin
- alteration in binding sites leading to decreased binding affinity
- increased expression of active efflux which enhances the transfer o f the FQs out of the cell
- alteration in cell wall permeability which prevents FQs from getting in
- cross-resistance is usually seen between the FQs
What are the PK characteristics of the FQs?
ciprofloxacin, levofloxacin, moxifloxacin, delafloxacin
- FQs display concentration-dependent bactericidal activity
- They are fast killers
Explain the SOA of FQs for GP aerobes:
- Cipro is no good for GP
- Newer agents like levo, moxi, and dela have enhanced GP activity
Which FQs are active against PRSP?
- levofloxacin
- moxifloxacin
- delafloxacin
Which FQ has activity against MRSA?
- delafloxacin
Describe the SOA of FQs for GN aerobes:
- cipro, levo, and dela have more activity
- covers pseudomonas aeruginosa
- They are the only oral agents potentially available for pseudomonas aeruginosa
Describe the SOA of FQs against atypical bacteria:
- FQs are one of the three classes that cover atypicals.
- FQs are extremely active against legionella
What are the PK benefits of FQs?
ciprofloxacin, levofloxacin, moxifloxacin, delafloxacin
- rapid killers
- display PAE
- well absorbed after oral administration
- extensive tissue penetration
- Post-antibiotic effect = PAE
- BA ranges from 50-90%
- AUC/MIC or peak/MIC correlates with clinical efficacy
Do FQs penetrate the CSF?
- Barely.
- They are not useful for meningitis
How are each of the FQs eliminated?
- levo is renally eliminated
- moxi is hepatically eliminated
- cipro and dela undergo both renal and hepatic elimination
- levo, cipro, and dela need dose-adjusted in renal dysfuntion
- None of the FQs are removed during HD
Which FQs have the greatest oral bioavailability?
Moxi and Levo
What are the adverse effects from FQs?
ciprofloxacin, levofloxacin, moxifloxacin, delafloxacin
- peripheral neuropathy –> BBW
- hepatotoxicity –> moxi
- QT prolongation –> Torsades
- Articular damage
- tendonitis/tendon rupture –> BBW
Which patients should FQs be used with caution in due to their ability to prolong the QT interval?
FQs should be used with caution in patients with:
- hypokalemia
- concomitant use of class III antiarrhythmics (amiodarone, sotalol)
- preexisting QTc prolongation
Which patients are contraindicated from using FQs and why?
- pediatric patients
- pregnancy
- breastfeeding
- CI due to adverse effect of articular damage/arthropathy.
What drugs interact with the FQs?
- cations
- warfarin
- cyclosporine (cipro only)
What is the interaction between divalent and trivalent cations and FQs?
- Zinc, iron, calcium, aluminum, magnesium (ZICAM)
- includes antacids, sucralfate, enteral feeds
The divalent and trivalent cations impair the absorption of any oral FQ due to chelation.
FQ doses should be given at least 2 hours before or 2-6 hours after these agents
What is the interaction between warfarin and FQs?
- Unknown interaction leading to increased prothrombin time and potential bleeding
What drug interactions does cipro have that haven’t been seen with the other agents?
- theophylline - increase theophylline concentrations
- cyclosporine - increased cyclosporin concentrations
