Effect of cimetidine on hepatic vitamin D metabolism in humans.
Cimetidine inhibits the action of vitamin D-hydroxylase (a hepatic mixed-function oxidase) in the rat. Therefore, the hypothesis was tested that this H2 receptor antagonist would affect vitamin D metabolism in humans. Nine adult patients were treated with 400 mg cimetidine orally twice daily during a period from winter to summer, when days were becoming longer. Serum levels of 25-hydroxyvitamin D, 24,25-dihydroxyvitamin D and 1,25-dihydroxyvitamin D were monitored before treatment, after 4 weeks of treatment, and 1 month after cessation of treatment. No seasonal increase in the level of 25-hydroxyvitamin D was observed during the period of treatment, but the level rose significantly after withdrawal of the drug. The other hydroxylates of vitamin D were not affected. Levels of albumin, total calcium, phosphorus and alkaline phosphatase remained normal. The data suggest that short-term treatment with cimetidine could potentially perturb vitamin D metabolism in man.
Odes
H S
HS
Gastroenterology Unit, Soroka Medical Center, Beer-Sheva, Israel.
Fraser
G M
GM
Krugliak
P
P
Lamprecht
S A
SA
Shany
S
S
D002927:Cimetidine / Q000627:therapeutic use*; D005260:Female; D006801:Humans; D006887:Hydroxycholecalciferols / Q000097:blood; D008099:Liver / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D010437:Peptic Ulcer / Q000188:drug therapy; D012621:Seasons; D014807:Vitamin D / Q000378:metabolism*
D006887:Hydroxycholecalciferols; D014807:Vitamin D; D002927:Cimetidine