Clinical meaning
The clinician prescribes outpatient CAP antibiotics based on patient comorbidity status and local resistance patterns. For previously healthy adults without recent antibiotic use, amoxicillin 1g TID is first-line (Canadian guidelines). For patients with comorbidities (COPD, diabetes, CKD, alcoholism, immunosuppression) or recent antibiotic use within 3 months, amoxicillin-clavulanate 875/125 BID plus a macrolide (azithromycin) or a respiratory fluoroquinolone (moxifloxacin, levofloxacin) as monotherapy are recommended. Duration of therapy is typically 5-7 days, guided by clinical response and procalcitonin levels. The clinician must consider drug allergies (cross-reactivity between penicillins and cephalosporins is < 2% with 3rd/4th generation), drug interactions (macrolides and QT prolongation, fluoroquinolones and warfarin), and patient factors (pregnancy, renal function, age).
Diagnosis & workup
Diagnostics & workup: - CXR to confirm diagnosis and assess severity - CRB-65 calculation to confirm outpatient suitability (score 0) - Pulse oximetry (SpO2 >= 94% for outpatient management) - Consider procalcitonin if viral vs bacterial etiology uncertain - Sputum culture not routinely indicated for outpatient CAP - Basic metabolic panel if comorbidities present