Fluoride bioavailability from slow-release sodium fluoride given with calcium citrate.
Clinical pharmacology of slow-release sodium fluoride given with calcium citrate was examined in acute and long-term studies. Following a single oral administration of 50 mg slow-release sodium fluoride, a peak serum fluoride concentration (Cmax) of 184 ng/ml was reached in 2 h; thereafter, serum fluoride concentration declined with a T1/2 of 5.9 h. The concurrent administration of calcium citrate (400 mg calcium) gave an equivalent Tmax (time required to attain Cmax) and T1/2, but a lower Cmax of 135 ng/ml. The coadministration of a meal with fluoride also reduced Cmax but increased Tmax. The area under the serum concentration curve of slow-release sodium fluoride was reduced 17-27% by a meal or calcium citrate. Thus, calcium citrate reduced fluoride absorption and peak fluoride concentration in serum of slow-release sodium fluoride but did not affect the time required to reach peak concentration or the rate of subsequent decline. The effect of a meal was similar, except for a longer period required to reach peak serum concentration. During long-term administration of 25 mg slow-release sodium fluoride coadministered with 400 mg calcium as calcium citrate on a twice daily schedule, the trough level of serum fluoride could be kept between 95 and 190 ng/ml, believed to be the therapeutic window.
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Center for Mineral Metabolism and Clinical Research, Southwestern Medical School, University of Texas Southwestern Medical Center, Dallas 75235-8885.
Sakhaee
K
K
Parcel
C
C
Poindexter
J
J
Adams
B
B
Bahar
A
A
Beckley
R
R
D000328:Adult; D001682:Biological Availability; D002951:Citrates / Q000494:pharmacology*; D019343:Citric Acid; D003692:Delayed-Action Preparations; D004347:Drug Interactions; D005260:Female; D005502:Food / Q000009:adverse effects; D006801:Humans; D008875:Middle Aged; D012969:Sodium Fluoride / Q000008:administration & dosage* / Q000493:pharmacokinetics*
D002951:Citrates; D003692:Delayed-Action Preparations; D019343:Citric Acid; D012969:Sodium Fluoride