Renal Tubular Acidosis Associated With Zonisamide Therapy

Inoue, Takehiko
Kira, Ryutaro
Kaku, Yoshitsugu
Ikeda, Kazuyuki
Gondo, Kenjiro
Hara, Toshiro

Department of Pediatrics, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan

Accepted August 9, 2000.

Address correspondence and reprint requests to Dr. Ryutaro Kira, at the Department of Pediatrics, Graduate School of Medical Sciences, Kyushu University, 3–1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan. E-mail: [email protected]

Epilepsia 41(12):p 1642-1644, December 2000.

Summary:

Purpose

We sought to report a previously undescribed adverse effect, renal tubular acidosis associated with zonisamide (ZNS) therapy.

Methods

Ammonium chloride, bicarbonate, and furosemide loading tests were performed in an epileptic patient with metabolic acidosis and episodic hypokalemia who was treated with ZNS.

Results

Distal renal tubular acidosis was diagnosed. On reexamination 7 weeks after ZNS had been replaced with phenytoin, the renal tubular acidosis disappeared.

Conclusions

This case indicates, for the first time, that ZNS might be a potential cause of renal tubular acidosis. Blood gases and serum electrolytes should be measured in patients undergoing ZNS therapy.