Effect of oral zoledronate administration on bone turnover in older women.

AIM: The aim of this work is to assess the safety and efficacy of two oral zoledronate preparations by determining their effects on bone resorption in healthy postmenopausal women. METHODS: The preparations studied were zoledronic acid in enteric-coated capsules or a microparticle preparation of zoledronic acid in these capsules. Bone resorption was measured as ß-C-telopeptideof type I collagen (CTX) in fasting serum. Separate cohorts, each of five women, were recruited and allocated in sequence to single doses of 20 mg, 40 mg, or 60 mg of oral zoledronate. RESULTS: Zoledronate 20 mg enteric capsules were well tolerated, reduced serum CTX by a median 51% at 1 week, but by only 17% at 1 month. Doses of 40 or 60 mg of this preparation produced APR and/or gastrointestinal symptoms in more than half of participants. With these doses, median CTX reduction at 1 week was >80%, ~70% at 1 month, but only ~30% at 6 months. Enteric capsules containing microparticles of zoledronate 20 mg reduced CTX by a median 53% at 1 week, with offset over 3 months. Two or three of these capsules dosed weekly reduced CTX by ~50% at 1 month, and by ~30% at 3 and 6 months. CONCLUSIONS: Oral zoledronate 20 mg circumvents the problem of APR symptoms but, even with multiple doses, the anti-resorptive effect is smaller and less sustained than with intravenous zoledronate. Probably a viable oral regimen of zoledronate dosing at intervals of weeks to months could be developed, but the advantage of infrequent dosing would be lost.

Effect of a Three-Day Course of Dexamethasone on Acute Phase Response Following Treatment With Zoledronate: A Randomized Controlled Trial.

Zoledronate is a potent intravenous bisphosphonate effective in the management of osteoporosis, Paget's disease and skeletal-related events in malignancy. Its most frequent adverse effect is the acute phase response (APR), an inflammatory reaction characterized by fever, musculoskeletal pain, headache, and nausea. This randomized, placebo-controlled, double-blind study investigated the efficacy of a three-day course of dexamethasone 4 mg daily in reducing incidence of APR. Participants (n = 60) were randomized to receive either 4 mg of oral dexamethasone 1.5 hours before zoledronate and once a day for the following 2 days, or placebo. Oral temperature was measured at baseline and three times a day for the following 3 days, and questionnaires assessing symptoms of the APR were completed at baseline and for 3 days following zoledronate. Use of anti-inflammatory medication in the 3 days following zoledronate was recorded. The primary outcome was the temperature change from baseline. There was a significant difference in the primary outcome between the dexamethasone and placebo groups (p < 0.0001), with a mean decrease in temperature of 0.10°C (95% confidence interval [CI], -0.34 to 0.14) in the dexamethasone group compared with a mean increase in temperature of 0.84°C (95% CI, 0.53-1.16) in the placebo group on the evening following zoledronate. There was also a difference in APR-related symptom score over time between the two groups (p = 0.0005), with a median change in symptom score in the dexamethasone group 1 day after zoledronate of 0 (95% CI, 0-1) compared with 3 (95% CI, 0-5) in the placebo group. An increase in temperature of ≥1°C to a temperature of >37.5°C occurred in two of 30 (6.7%) participants in the dexamethasone group compared with 14 of 30 participants (46.7%) in the placebo group (p = 0.0005). This study demonstrates that a 3-day course of dexamethasone substantially reduces the APR following zoledronate infusion. © 2023 American Society for Bone and Mineral Research (ASBMR).