Alternate calcitonin and etidronate disodium therapy for Paget's bone disease

The efficacy of salmon calcitonin and etidronate disodium was compared in the therapy of Paget's bone disease in 37 patients. Nineteen patients received etidronate for six months with a mean alkaline phosphatase reduction to 53% of initial values. Bone scintophotographs improved in 12 and were unchanged in seven. Symptoms improved in 11 subjects, were unchanged in seven, and worsened in one. Twelve of these patients were then treated with calcitonin for six months with continued improvement in alkaline phosphatase values to 36% of initial values. All bone scintophotographs improved compared with initial studies. Seven patients continued to improve symptomatically; five described no change. Eighteen individuals were treated initially with calcitonin for six months. During therapy, the alkaline phosphatase level fell to 76% of initial values. Bone scintophotographs were worse in two patients, did not change in seven, and improved in nine. Eleven patients reported improvement in symptoms and seven reported no change. Seventeen of these patients were then treated with etidronate for six months with a decrease in alkaline phosphatase levels to 64% of initial values. Compared with initial tests, bone scintophotographs were worse in three with no change in five and improvement in nine. Symptomatically, three patients reported improvement; four noted no change, and ten reported increasing pain. Although the reason for the poor response to initial calcitonin therapy and/or subsequent etidronate therapy is not apparent, we have concluded that patients fare better when treated with an etidronate calcitonin sequence when compared with those treated with a calcitonin/etidronate sequence.