Levine BS, Song M
Pharmacokinetics and efficiency of pulse oral versus intravenous
calcitriol in hemodialysis patients
J Am Soc Nephrol
(Mar) 7:488-496 1996
The authors investigated the pharmacokinetics of calcitriol in 16
hemodialysis patients randomized to receive it by either the oral
or IV route. Patients received 2 ug after each dialysis for 3
weeks. Kinetic studies were done after the 2nd and 8th dialysis.
With the IV route, there were greater peak levels and areas under
the curve up to 1 hr post administration. Thereafter, the areas
under the curve were similar as were the plasma half-lives.
Overall, the plasma half-lives were shorter during the second
Fifteen patients were successfully randomized to receive either
oral or IV calcitriol for 21 weeks to compare their clinical
efficacy. Serum calcium levels increased and PTH levels
decreased to a similar degree in both groups. Similarly, the
incidence of hypercalcemia and high Ca x P product was the same.
The mean dose of calcitriol was 2 ug in each group. The authors
conclude that pulse oral and IV calcitriol are equally
efficacious in suppressing PTH levels in hemodialysis patients
despite higher peak calcitriol values seen with the IV route.
Comment: The study largely confirms and extends prior studies.
See Clin Nephrol 40:216-220, 1993 and Kidney Int 45:1710-1721,
1994. Well written discussion section. (James A. Delmez, M.D., Washington
University at St. Louis)