Treatment of Wilson's disease with zinc XII: dose regimen requirements

A considerable body of data is now available indicating the efficacy and lack of toxicity of zinc treatment of Wilson's disease. Dose-response studies have shown that regimens of 50 mg of elemental zinc 3 times a day (50 mg x 3), 25 mg x 3, and 50 mg x 2 are effective, but 25 mg x 2 and 50 mg x 1 are not adequately effective. These studies indicate that 75 mg a day is close to the minimally effective dose, but do not address the question of necessary dose frequency. In the current study, the authors have used the minimally effective daily dose, 75 mg, and studied this daily dose in regimens of 25 mg x 3, 37.5 mg x 2, and 75 mg x 1 in treatment of four patients with Wilson's disease. These data have been supplemented with additional data from 11 patients treated with 25 mg 3 times a day and with data from 2 patients treated with 75 mg once a day. Efficacy was evaluated by 10-day copper balance and absorption of orally administered 64copper. The findings indicate that a daily dose of 75 mg must be divided into at least two doses to be effective, and that the 64copper procedure is more sensitive to zinc dose than copper balance.