Medicines and treatments for adults with pneumonia. The treatment for your pneumonia will depend on what is causing it (i.e. a viral or bacterial infection). Pneumonia in adults is usually caused by bacteria. If bacteria are causing the infection, your doctor will prescribe antibiotics.The antibiotic that is most appropriate for you depends on what type of bacteria is causing the infection, and how severe your symptoms are. Less severe pneumonia infections can be treated with antibiotics at home.If you haven’t improved at all 2 days after you start antibiotic treatment, or your symptoms get worse, see your doctor. Find out how to relieve the symptoms of pneumonia.ess severe pneumonia infections can be treated with antibiotics at home. If you haven’t improved at all 2 days after you start antibiotic treatment, or your symptoms get worse, see your doctor. Find out how to relieve the symptoms of pneumonia.