I was on 75 mg of Topamax for 6 months. I became unable to empty my bladder. I was taking Cardura high blood pressure meds to release the bladder muscle. Even had to have a cystoscope. My urologist did not think it was the Topamax causing the problem. Finally I decided to get off Topamax on my own. Its been a week now and I m totally cured. This drug was a horror!