The study period will be at least three weeks from the start of screening to the end of analgesic response. Patients will be screened for the study and will enter a 4- to 7-day baseline period within 28 days of screening. Following the baseline period, patients will either be admitted to the hospital or be seen at the site's outpatient facility on a daily basis. Patients will be randomized on Day 1 to receive study drug twice daily for four consecutive days. After the treatment period, all patients will be seen again on Days 5, 8, and 15 for further safety and efficacy evaluations, and then every two weeks until their pain returns.