A 62-year-old client presents with a complaint of fever, pain, and burning on urination. Difficulty urinating with dribbling has been increasing in the past few days. He has a feeling of pressure in his groin. On examination, his prostate is tender, boggy, and warm. A stat urinalysis reveals the presence of leukocytes and bacteria. He is allergic to sulfa drugs. His weight is 70 kg and his:.