Pseudogout attack induced during etidronate disodium therapy.

We report the first case of pseudogout attack in the distal interphalangeal (DIP) joints during etidronate disodium therapy. A 64-year-old woman had intermittent administration of etidronate disodium (Didronel; Sumitomo, Osaka, Japan) alone because of osteoporosis. Each cycle consisted of a daily dose of 200 mg for 2 weeks, repeating every 12 weeks.