- Patients with AIDS or AIDS related diseases who have had AZT intolerance that required cessation of therapy. This is an outpatient study; patients are seen weekly for the first 4 weeks, every other week through week 12, and then every 4 weeks for the duration of the 24 weeks of the treatment portion of the study. Patients from each of the three diagnostic groups are enrolled at each dose level. For the first 3 days after entry into the study, all patients receive the lowest dose of RBV every 6 hours. Subsequent dosages increase until the maximum tolerated dose (MTD) is reached. The MTD for a group is defined as the dose at which 4 or more of the 8 patients in the group develop toxicity which requires a change or discontinuation of the dosage.