the double-edged sword
Potent broad-spectrum bactericidal agents (DNA gyrase inhibitors) with excellent bioavailability (PO = IV). Highly effective but plagued by “collateral damage” (C. diff, tendon rupture, aneurysm).
agents & spectrum
| Drug | Spectrum | Key Role |
|---|---|---|
| Ciprofloxacin | Gram Negatives (Inc. Pseudomonas). Poor Gram Positive. | UTIs (Pyelonephritis), Intra-abdominal (w/ Flagyl), Febrile Neutropenia (Step-down). |
| Levofloxacin | Gram Neg + Streptococcus (“Respiratory FQ”). | CAP (Pneumonia), Legionella. |
| Moxifloxacin | Gram Neg + Strep + Anaerobes. | Aspiration Pneumonia, Intra-abdominal. No renal adjustment. |
adverse effects
- Black Box Warnings:
- Tendonitis/Rupture: Achilles tendon (esp. elderly/steroids).
- Aortic Aneurysm Rupture: Avoid in Marfan/Ehlers-Danlos.
- Neuropathy: Permanent peripheral neuropathy.
- C. difficile: Highest risk antibiotic class.
- QT Prolongation: Moxifloxacin > Levo > Cipro.
- Dysglycemia: Hyper/Hypoglycemia.
contraindications
- Pregnancy/Children (Cartilage damage - theoretical).
- History of Myasthenia Gravis (Exacerbates weakness).