Pharmacokinetic and pharmacodynamic comparison of two calcium supplements in postmenopausal women

H. J. Heller, L. G. Greer, S. D. Haynes, J. R. Poindexter, C. Y C Pak

Research output: Contribution to journalArticlepeer-review

77 Scopus citations


This randomized crossover study compared the single-dose bioavailability and effects on parathyroid function of two commercially formulated calcium supplements containing 500 mg of elemental calcium. Twenty-five postmenopausal women underwent three phases of study wherein they each took a single dose of calcium citrate with a standard breakfast (as Citracal® 250 mg+ D), calcium carbonate (as Os-Cal® 500 mg+ D), or placebo at 8 a.m. Blood samples were drawn at baseline and hourly for 4 or 6 hours after each dose. Fasting and postload urine samples were also collected. Compared with calcium carbonate, calcium citrate provided a 46% greater peak-basal variation and 94% higher change in area under the curve for serum calcium and a 41% greater increment in urinary calcium. Moreover, the decrement in serum parathyroid hormone concentration from baseline was greater after calcium citrate. In conclusion, calcium citrate is more bioavailable than calcium carbonate when given with a meal. (C) 2000 the American College of Clinical Pharmacology.

Original languageEnglish (US)
Pages (from-to)1237-1244
Number of pages8
JournalJournal of clinical pharmacology
Issue number11
StatePublished - 2000

ASJC Scopus subject areas

  • Pharmacology
  • Pharmacology (medical)


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