Effects of two oral doses of alendronate in the treatment of Paget's disease of bone.

Twenty patients with mild Paget's disease of bone were given either 20 (10 patients) or 40 mg alendronate daily for 6 months. The 20-mg dose was well tolerated, but in 3 patients on 40 mg/d alendronate, the treatment was withdrawn after 3-5 months because of gastric and oesophageal disturbances. Urinary hydroxyproline excretion fell within the first month to 77 +/- 5% (SD) and to 47 +/- 5% of pretreatment values in the 20- and 40-mg dosing group, respectively (p < 0.001 between group comparison). The serum alkaline phosphatase fell more slowly with the maximum suppression of disease activity reached at 4 months, when it attained a plateau in both groups of patients. However, the decrease in serum alkaline phosphatase was significantly more pronounced in the patients treated with 40 mg/d tablets (50 +/- 10% of pretreatment values) than in those given 20 mg alendronate per day (76 +/- 9% of initial value), in none of whom a disease remission was observed. It appears, therefore, that while 20 mg/d oral doses of alendronate are insufficient, 40 mg/d are associated with a high incidence of side effects. Furthermore, the suppression of disease activity depends on the dose of bisphosphonate given daily or over a short period of time and lower doses cannot be compensated by a longer duration of the treatment course.