Which of the following is the most appropriate loading dose of this drug for this patient (in mg)? A 76-year-old man is admitted to the hospital because of a 2-week history of a persistent urinary tract infection. He is 165 cm (5 ft 5 in) and weighs 55 kg (121 lb); BMI is 20 kg/m2. The physician plans to initiate treatment. A component of the initial treatment includes an intravenous bolus dose of an antibiotic to attain an initial peak serum concentration of 8 mg/L. The volume of distribution of the antibiotic is 0.35 L/kg. Laboratory studies show a 24hour urine creatinine clearance within the reference range.