Symptomatic UTI in a 30-Week Pregnancy

A 30-year-old woman, gravida 2 para 1, at 30 weeks of gestation, presents to the antenatal clinic with a two-day history of dysuria, urinary frequency, and suprapubic discomfort. She has no fever or flank pain. Her past medical history is unremarkable. She takes no regular medications. She reports an allergy to penicillin. On examination, temperature 36.9°C, pulse 82/min, blood pressure 118/74 mmHg, respiratory rate 14/min. Abdomen is soft with mild suprapubic tenderness, uterine size consistent with 30 weeks. Laboratory results: serum creatinine 0.6 mg/dL, eGFR 115 mL/min/1.73 m2. Urine dipstick: leucocyte esterase +++, nitrites positive. Microscopy: numerous white blood cells and bacteria. Weight 68 kg. The urine culture is pending. Write a prescription for an appropriate oral antibiotic for this patient.