A Study to Compare the Safety and Effectiveness of 2 Doses of Levofloxacin Given for Different Time Periods in Patients With Pneumonia

Inclusion Criteria: Diagnosis of community-acquired pneumonia as follows: clinical signs and symptoms of a lower respiratory tract infection and chest-x-ray findings consistent with pneumonia within 24 hours before entry into the study At least one of the following: abnormal temperature (high or low) or abnormal white blood cell count Previous antibiotic treatment <= 24 hours or, if the duration of treatment was >= 72 hours and that therapy failed based on at least 2 of the following: fever within 12 hours of entry into the study, chest x-ray findings have worsened compared to the initial chest-x-ray, white blood cell count is significantly increased, respiratory rate higher than at the start of treatment and >= 20 breaths per minute or need for supplemental oxygen if not previously needed Patients whose infection is acquired in the community or, if in a nursing home, who had been living there < 14 days Fine Class (rating scale used to assess patients' overall condition which includes information such as age, gender, other diseases, physical examination and laboratory findings) score <= 130 upon admission (patients with Fine Class scores > 70 but < = 130 must initially be hospitalized Patients with scores of <= 70 may be treated as outpatients or hospitalized at the discretion of the investigator) Exclusion Criteria: Pneumonia known or suspected to be due to a bacteria resistant to levofloxacin Previous allergic or serious reaction to or failed therapy with levofloxacin or similar drugs Life expectancy < 72 hours Hospitalized within 2 weeks before entry in the study or within 1 month before entry in the study if treated with antibiotics Pneumonia acquired in a hospital Cystic fibrosis or other lung disorders Receiving chronic steroid treatment Received assistance from a machine to breathe within the previous month