What Caused Sudden Onset Of Brown Discharge And Spotting ?

I am 61 years of age. Recently I have started a discharge which I never had before. No oder and I thought it was urine. I started taking Azo Standard blader control. After about 2 weeks I stared a brownish discharge. No pain like cramps I just started with a light brown discharge. I stopped taking them and I did douche and brownish stuff came out then it cleared up. Now today it started again a very small spot.