Brown discharge on day 3 of nitrofurantoin mono mac for uti on day periods due on birth control pills no cramps. dull back ache normal?

See answer: Nitrofurantion taken for 5-7 days usually a good antibiotic for a simple bladder infection but not a good choice if kidney infection is suspected (fever, chills, flank pain, nausea, feeling sick). Your symptoms of brownish vaginal discharge and dull backache (if low), suggest a gynecological origin unrelated to your UTI (pending or abnormal period, vaginitis, etc). If persists/worsens, call md.