Provided is the use of ceftaroline fosamil in the treatment of a complicated skin and skin structure infection or community-acquired bacterial pneumonia, in a patient having impaired renal function with creatinine clearance of less than 50ml/min, wherein said treatment comprises providing a dosage form comprising about 300 mg of ceftaroline fosamil and L-arginine and adding about 20 ml of sterile water to the dosage form to form a constituted solution that has a pH of about 4.8 to about 6.5 and administration of the constituted solution to the patient intravenously every 12 hours by infusion over one hour.
