Keflex for Sinus Infections: What You Need to Know

Keflex (cephalexin) is a first-generation cephalosporin active against common sinus pathogens (S. pneumoniae, H. influenzae, M. catarrhalis). However:

• Not first-line for acute bacterial sinusitis (amoxicillin/clavulanate preferred).
• Ineffective against viral sinusitis (most cases).
• Resistance patterns vary by region.

Antibiotic selection should follow evidence-based guidelines (IDSA, AAO-HNS) and consider allergy history, local resistance, and severity. Never self-prescribe or adjust antibiotics.