Initially, daily dosage was 4.5 grams in three divided doses of 1.5 gram every two hours. A dose reduction to 3.0 gm. per day was made after recognition of possible cardiac toxicity in other studies that were ongoing simultaneously. Bropirimine was taken for 12 consecutive weeks

Bone marrow cells (BMCs) were collected from femora and tibiae of 6-week-old male C57BL/6 mice, and cultured for 6 h in alphaMEM containing 10% fetal bovine serum (FBS) in Petri dishes. Mouse BMCs (1 x 105 cells/well) and mouse osteoblastic UAMS- 32 cells were co-cultured in 96-well plates for 4 days in aMEM supplemented with 10% FBS in the absence or presence of 1alpha,25(OH)2D3 (10 nmol/L), and various concentrations of bropirimine. Medium was replaced with fresh containing the same supplemental agents on day 3. As described above, TRAP activity staining was employed to evaluate osteoclast differentiation.