Cancer patients with painful osteolytic bone metastases who had failed initial treatment with hormones and/or chemotherapy were each randomized to receive one of three pamidronate doses as outpatients: 45, 60, 90 mg given every 3 weeks for 12 weeks. Seventy patients were enrolled in this study, for a total of 265 infusions. There were 64 patients who completed 12 weeks of therapy. Forty-eight patients took nonsteroidal antinflammatory drugs, while 22 patients received morphine before pamidronate treatment. A reduction in bone pain and mobility scores was observed in all three different dose groups: in 11 of 23 patients (47%) at 45 mg; in 12 of 24 patients (50%) at 60 mg; and in 16 of 23 patients (69%) at 90 mg. However, while for patients receiving pamidronate at 90 mg median changes in pain and mobility were statistically significant at the 6th week, for patients receiving 45 mg they were not significant until the 12th week and for patients receiving 60 mg, until the 9th week. In weeks 0-6, the daily consumption of analgesics was reduced in 3 patients in the 45-mg arm, in 4 patients in the 60-mg arm, and in 7 patients in the 90-mg arm. In weeks 7-12, the daily consumption of analgesics was reduced in 8 patients receiving 45 mg, in 8 patients receiving 60 mg, and in 7 patients receiving 90 mg. No significant toxicity was recorded. In 2 patients (45 and 90 mg) fever (> 38 degrees C) and myalgia were observed after the first administration. In conclusion, our results seem to confirm the utility of higher doses of pamidronate in patients with painful bone metastases, because of the faster symptom relief achieved.