Followup visits were scheduled weekly for the first 4 weeks, monthly for the next 2 months, and every 3 months thereafter. For patients assigned to the titration protocol, additional visits were made at weeks 5 and 6. A complete history was recorded and a physical examination was conducted every 15 months; electrocardiogram was recorded every 6 months. In addition, patients were cautioned to note any signs of hypersensitivity.