A 45-year-old previously well woman presents to her GP with a 3-day history of fever, productive cough and pleuritic chest pain. She has a temperature of 38.3 °C, heart rate 96 bpm, blood pressure 122/74 mmHg, respiratory rate 20 breaths/min and oxygen saturation 97% on room air. Chest examination reveals right lower zone crackles. CURB-65 score is 0. She has no significant comorbidities and no antibiotic use in the past 3 months. What is the most appropriate empiric oral antibiotic regimen?