Intermittent versus continuous clodronate administration in postmenopausalwomen with low bone mass

The aim of the study was to compare the effects on bone mass and turnover o f continuous vs. intermittent clodronate administration on 120 postmenopaus al women (average age 61 years) with low bone mass (femoral neck bone miner al density [BMD] of at least -1 SD or more, T-score), with another 30 women as a control group. Participants were given 1800 mg of clodronate every 6 months over 2 years using different treatment patterns: a) two continuous r egimens, consisting of a daily oral dose of 400 mg or 100 mg every 10 days by intramuscular injection, the latter being considered continuous because the interval between injections is shorter than the time employed by each b one remodelling unit to complete the resorption phase of a remodelling cycl e; and b) two intermittent regimens, consisting of 1800 mg every 6 months a dministered either as a single 18-h intravenous infusion or by separate inf usions of 300 mg over 6 consecutive days. All women, including those in the control group, received calcium and vitamin D supplementation. After 2 yea rs, continuous clodronate regimens caused an increase in BRID both at lumba r spine and proximal femur (L1-4 BMD = 3.07% and 2.69%; femoral neck = 2.12 % and 2.09%, respectively, with intramuscular and oral regimens). Intermitt ent clodronate administration was associated with a small increase or a sta bilization in bone mass (L1-4 BMD = 0.53% and 1.22%; femoral neck = 0.30% a nd 0.77%, respectively, with 1- and 6-day intravenous infusion regimens). F rom the 12th month, changes in spine and femoral neck BRID after continuous regimens were statistically different compared with that obtained with int ermittent ones. Twenty-five of the 150 women (16.7%) discontinued the study before the end of the 2-year follow-up, but of these, only 7 dropped out b ecause of adverse events related to the treatment itself. To summarize, int ermittent clodronate administration could be a suitable option for the prev ention of osteoporosis. (C) 2000 by Elsevier Science Inc. All rights reserv ed.