What Antibiotics Should Be Used for Bacterial Sinusitis?

Acute bacterial sinusitis is a common upper respiratory infection characterized by inflammation of the paranasal sinuses, typically following a viral upper respiratory tract infection. Diagnosis requires the presence of persistent symptoms—such as purulent nasal discharge, facial pain or pressure, and nasal obstruction—for at least 10 days without improvement, or worsening after initial improvement (“double-sickening”), or severe onset with high fever and marked toxicity.

Antibiotic therapy is indicated only when clinical criteria strongly suggest a bacterial etiology, as most cases of acute sinusitis are viral and self-limiting. First-line treatment for adults and children is amoxicillin, administered at a dose of 500 mg three times daily or 875 mg twice daily for adults, and weight-based dosing (45–90 mg/kg/day in two or three divided doses) for pediatric patients. Amoxicillin-clavulanate is recommended as initial therapy in patients with risk factors for resistant pathogens—including recent antibiotic use (within the past 4–6 weeks), severe illness, hospital-acquired infection, or attendance at daycare—due to its broader spectrum against beta-lactamase–producing strains of *Haemophilus influenzae* and *Moraxella catarrhalis*.

Alternative agents—such as cefuroxime, cefpodoxime, or levofloxacin—are reserved for documented penicillin allergy (non-type I), treatment failure after appropriate amoxicillin-clavulanate courses, or confirmed resistance patterns. Fluoroquinolones should be used sparingly and only when no suitable alternatives exist, given concerns about tendon toxicity, neuropathy, and antimicrobial stewardship.

It is critical to emphasize that antibiotics do not replace supportive care. Saline nasal irrigation, intranasal corticosteroids (e.g., mometasone or fluticasone), adequate hydration, and analgesia remain foundational components of management. Duration of antibiotic therapy is typically 5–7 days for mild-to-moderate cases in adults; longer courses (up to 10–14 days) may be considered in severe or complicated presentations, though evidence supporting extended duration is limited.

Prescribing decisions must always be individualized, incorporating local resistance patterns, patient comorbidities, medication tolerability, and adherence considerations. Unnecessary or inappropriate antibiotic use contributes to antimicrobial resistance and increases the risk of adverse drug reactions—underscoring the importance of judicious, evidence-based prescribing in acute bacterial sinusitis.