A 48-year-old otherwise healthy man presents with 3 days of fever (38.2 °C), productive cough and right-sided pleuritic chest pain. Respiratory rate is 20 breaths/min, BP 125/75 mmHg, saturations 96% on room air and he is alert. Chest examination reveals crackles in the right lower zone; chest X-ray shows a right lower lobe consolidation. He has no comorbidities and takes no regular medications. What is the most appropriate initial antibiotic management?