Comparison of twice a day and three times a day meropenem administration in elderly patients in a Japanese community hospital

Meropenem (MEPM) is a broad-spectrum antibiotic prescribed to patients with moderate or severe pneumonia. It is well recognized that appropriate medicine reduces the burden on not only young patients but elderly ones as well. We enrolled 56 patients aged 75 and over who were diagnosed with moderate or severe pneumonia (body temperature: ≧37.5 °C; white blood cell (WBC) count: ≧10,000/μL; C-reactive protein (CRP): ≧4 mg/dL) on the basis of Clinical Evaluation Methods for New Antimicrobial Agents to Treat Respiratory Infections defined by the Japanese Society of Chemotherapy, at the National Hospital Organization Kanazawa Medical Center from January 1, 2007 to May 31, 2010. Forty-two patients were given MEPM twice a day and 14 were given the same drug three times a day in a Japanese community hospital. After four days, the three times a day group showed significant decreases in body temperature, WBC count, and CRP level, which are commonly used indices for evaluating therapeutic effects. Similarly, the twice a day group showed decreases of those indices, and both treatments had no serious adverse effects. Simulation analysis based on the pharmacokinetics-pharmacodynamics (PK/PD) theory revealed that both treatments effectively inhibited the activities of Pneumococcus, Haemophilus influenzae, Providencia stuartii, and Staphylococcus aureus, which are the major bacteria in the patients. In this retrospective study, simulation analysis based on the PK/PD theory revealed that even the twice a day MEPM administration has sufficient effectiveness against pneumonia. It also may pave the way for the use of personalized medicine in the patients.