Ciprofloxacin
Cipro
Fluoroquinolone antibiotic
Inhibits DNA gyrase/topoisomerase IV → blocks DNA replication. Gram-negative (incl. Pseudomonas) focus.
Indications
- •UTI/pyelonephritis, GI infections, pseudomonal coverage, anthrax
Dosing
| Context | Adult | Pediatric |
|---|---|---|
| Typical | 400 mg IV q8–12h (or 500–750 mg PO) | — |
Pharmacokinetics
Half-life ~4 h. Renal + hepatic. Excellent oral bioavailability.
Side effects
- !QT prolongation
- !Tendon rupture / tendinopathy (Black Box, esp. elderly/steroids)
- !Aortic aneurysm/dissection risk
- !CNS effects/seizure lowering
- !C. difficile
- !↑ warfarin/theophylline levels
Contraindications
- ×Long QT
- ×Myasthenia gravis (exacerbation)
- ×Tendon disorder history
- ×Pregnancy/children (relative — cartilage)
Clinical pearls
- ★Class Black-Box harms: tendon rupture, aortic dissection, worsened myasthenia gravis, CNS/QT effects — reserve for when needed.
- ★Inhibits CYP1A2 → raises theophylline; potentiates warfarin.
Other drugs in Antibiotics
- Cefazolin
β-lactam — inhibits bacterial cell wall PBPs.
- Vancomycin
Inhibits cell wall synthesis (binds D-Ala-D-Ala). Active against MRSA + gram-positives.
- Clindamycin
Binds 50S ribosomal subunit, blocks peptide-bond formation. Bacteriostatic against most organisms; bactericidal against susceptible streptococci. Excellent activity against anaerobes and gram-positive cocci including community-acquired MRSA.
- Gentamicin
Binds 30S ribosomal subunit, causes misreading of mRNA → defective bacterial protein synthesis. Bactericidal, concentration-dependent killing. Synergy with cell-wall agents (β-lactams, vancomycin) for gram-positive endocarditis.
- Cefuroxime
β-lactam — inhibits cell-wall synthesis (PBP binding). 2nd-gen: gram-positive + expanded gram-negative.
- Cefepime
β-lactam cell-wall inhibitor. Broad gram-negative (incl. Pseudomonas) + gram-positive coverage.
- Cefotetan
β-lactam; adds anaerobic (B. fragilis) coverage → colorectal/gynecologic prophylaxis.
Suggested reading
- •Miller's Anesthesia, 9e
- •FDA package insert
