Chapter 23: Respiratory Infections – Antibiotic & Antiviral Use

Chapter 23 offers a comprehensive analysis of upper and lower respiratory tract infections (RTIs), emphasizing critical differentiation and appropriate pharmacologic management for conditions ranging from the common cold to community-acquired pneumonia (CAP). Upper RTIs, including the common cold (often viral, such as rhinovirus) and rhinosinusitis, are predominantly treated with supportive measures and symptomatic relief using agents like decongestants (e.g., oxymetazoline, pseudoephedrine), antitussives (e.g., dextromethorphan), and nonsteroidal anti-inflammatory drugs (NSAIDs). A key clinical focus is distinguishing acute viral rhinosinusitis (AVRS) from acute bacterial rhinosinusitis (ABRS) based on symptom duration and severity, guiding decisions on initiating antibiotics. For ABRS, first-line empiric therapy typically involves amoxicillin-clavulanate, with alternatives like doxycycline or levofloxacin reserved for penicillin-allergic patients or second-line treatment. The chapter addresses lower RTIs, highlighting acute bronchitis as usually viral and self-limiting, cautioning strongly against routine antibiotic use, but recommends antivirals such as oseltamivir if influenza is suspected. Finally, the management of outpatient CAP requires empirical antibiotic regimens, often utilizing beta-lactams (e.g., amoxicillin), macrolides (e.g., azithromycin), or respiratory fluoroquinolones, tailored according to patient comorbidities and risk factors for resistant organisms. Throughout the discussion, the sources stress the importance of antimicrobial stewardship to prevent resistance and encourage thorough patient education regarding appropriate hygiene and when professional care is necessary.