Silicate Urolithiasis during Long-Term Treatment with Zonisamide.
Silicate urinary calculi are rare in humans, with an incidence of 0.2% of all urinary calculi. Most cases were related to excess ingestion of silicate, typically by taking magnesium trisilicate as an antacid for peptic ulcers over a long period of time; however, there also existed unrelated cases, whose mechanism of development remains unclear. On the other hand, zonisamide, a newer antiepileptic drug, is one of the important causing agents of iatrogenic urinary stones in patients with epilepsy. The supposed mechanism is that zonisamide induces urine alkalinization and then promotes crystallization of urine components such as calcium phosphate by inhibition of carbonate dehydratase in renal tubular epithelial cells. Here, we report a case of silicate urolithiasis during long-term treatment with zonisamide without magnesium trisilicate intake and discuss the etiology of the disease by examining the silicate concentration in his urine.
Department of Urology, Tokyo Teishin Hospital, Tokyo 102-8798, Japan ; Department of Urology, Graduate School of Medicine, The University of Tokyo, Tokyo 113-8655, Japan.
Satoru
S
Taguchi
Yorito
Y
Nose
Toshikazu
T
Sato
Teruaki
T
Kobayashi
Kanami
K
Takaya
Akira
A
Ishikawa
Yukio
Y
Homma