SHORT-TERM EFFECTS OF PAMIDRONATE ON BIOCHEMICAL MARKERS OF BONE METABOLISM IN OSTEOPOROSIS - A PLACEBO-CONTROLLED DOSE-FINDING STUDY

The bisphosphonates are potent inhibitors of osteoclastic bone resorption that mainly have been used for treatment of hypercalcaemia secondary to malignancy. We have performed a controlled dose-finding study of oral pamidronate that was given to 60 patients with a history of fracture of the distal forearm, an enhanced bone turnover and a lowered bone mineral density. Different doses of pamidronate, 75 mg and 150 mg daily, or placebo were given to parallel groups. Fasting specimens of blood and urine were collected before the treatment period and at regular intervals. Oral pamidronate caused a dose-related reduction on the biochemical markers of bone resorption, i.e. fasting urinary calcium, hydroxyproline, pyridinoline and deoxypyridinoline that was seen already after the first week. The inhibition was evident during the treatment period and 4 weeks thereafter but not 12 weeks after cessation of therapy. Also the levels of serum osteocalcin, a marker of bone formation, were lowered during treatment with the higher dose.