A 22-year-old young man came to a doctor with complaints of fever and cough with yellow sputum. These symptoms have been observed for the last seven days. Physical examination shows the following: body temperature 38.3° C, blood pressure-130/70 mm Hg, heart rate-79 /min., respiratory rate. 17 /min., SpO₂- 95 %. Auscultation detects moist crackles on the left. Survey X-ray of the chest reveals left lower lobe consolidations. What drug should be prescribed to the patient in this case?