Combined Calcitriol-Pamidronate Therapy For Bone Hyperresorption In Spinal Cord Injury

Abstract

Objective: To determine the biochemical effects of combined calcitriol-pamidronate therapy on bone hyperresorption in patients with spinal cord injury (SCI).Methods: This was a retrospective study of 21 SCI inpatients (4 women and 17 men, mean age 34 years) treated for bone hyperresorption. Initial treatment was 0.5 ~-tg oral calcitriol once daily and 1250 mg CaC03 twice a day (1000 mg elemental calcium/day). On days 4 through 6 following the initial treatment, patients received 30 mg pamidronate intravenously once daily (total of 3 doses). Urinary N-telopeptide (NTx) and calcium excretion rates, and serum parathyroid hormone (PTH), 25-hydroxyvitamin D (25-D) , 1,25-dihydroxyvitamin D (1 ,25-D), calcium, and phosphorus levels were measured within 2 weeks prior to and 2 weeks following pamidronate therapy.Results: Patients demonstrated increased urinary NTx and calcium excretion, indicative of bone hyperresorption, and suppressed PTH and 1 ,25-D levels as early as 9 days post-SCI. Combined calcitriol-pamidronate therapy decreased urinary NTx and calcium excretion by 71% (P < .001) and 73% (P < .001 ), respectively. This therapy also increased serum levels of PTH (P <.05) and 1 ,25-D (P < .005). Post-pamidronate hypocalcemia or hypophosphatemia was observed in 44% (P < .01) or 53% (P < .01 ), respectively.Conclusion: Combined calcitriol-pamidronate therapy significantly inhibited bone hyperresorption in SCI patients.J Spinal Cord Med. 2001 ;24:235-240