Amoxicillin for Sinusitis: Timeline for Improvement

Amoxicillin (often with clavulanate as Augmentin) is a first-line antibiotic for acute bacterial sinusitis.

• Typical response: Symptom improvement within 48–72 hours of starting therapy.
• Full course: Usually 5–10 days (guidelines vary). Complete the prescribed course even if feeling better to prevent resistance and relapse.
• No improvement at 72 hours: Contact your clinician—may need reassessment, culture, or alternative antibiotic (e.g., respiratory fluoroquinolone, doxycycline).
• Worsening symptoms: Seek urgent care (possible orbital/intracranial complication).

Note: Most acute sinusitis is viral; antibiotics are reserved for bacterial criteria (≥10 days without improvement, severe onset, or "double worsening").