[Combination or sequential treatment using PTH and anti-resorption therapies].

PTH increases bone formation and has an anabolic effect on bone. Antiresorptive drugs such as bishopshonateand selective estrogen receptor modulator (SERM) inhibit bone resorption and increase bone mineral density (BMD) . Efficacy of combinationtreatment with PTH and antiresorption drugshas been investigated. It has been reported that single intravenous infusion of zoledronic acid along with daily subcutaneous injection of PTH (1-34) (teriparatide) increases both spine and hip BMD. On the other hand, daily oral alendronate and daily PTH (1-84) showed no additive effects. Patients who had been treated with antiresorption drugs showed somewhat blunt but significant positive response to teriparatide. It warrants sequential therapy with teriparatide following antiresorption drugs that is common in daily practice of osteoporosis. Since a period of PTH administration is limited up to 24 months and bone mineral density starts to decreases shortly after discontinuation of PTH, sequential treatment with antiresorptive agents following PTH is highly recommended.