The dissolutive effects of sodium fluoride on human calcium stone part
icles were investigated in an in vitro model. Stone particles composed
of 65% calcium oxalate and 35% calcium phosphate dissolved in a dose-
dependent fashion with NaF exposure. Stone particles exposed to 60 mM
NaF had a 17% reduction in particle mass after 24 hours and a 62% redu
ction after 7 days in comparison with experimental controls bathed in
physiologic normal saline. The systemic toxicity of the dose of oral f
luoride necessary to achieve the optimal tested urinary concentrations
would likely preclude oral administration, but NaF may have an adjunc
tive role in upper urinary tract irrigation for residual stone fragmen
ts after lithotripsy or in chronic low-dose oral administration for pr
ophylaxis against recurrent calcium nephrolithiasis.