OUTLINE: This is a randomized study. Patients are randomized to 1 of 2 treatment arms. Arm I: Patients receive oral pentosan polysulfate three times a day for 2-6 months. Arm II: Patients receive oral placebo three times a day for 2-6 months. Both arms: Patients may receive retreatment for two months if symptoms return and last for at least 2 weeks. Quality of life is assessed before treatment, and at each follow up visit. Patients are followed every 2 months for 6 months, then every 3 months for 18 months, then annually for 3 years.