Effect of long-term administration of anticonvulsants on copper, zinc, and ceruloplasmin levels.

Anticonvulsant therapy is known to be associated with elevated plasma copper and ceruloplasmin levels. To investigate the effect of long-term phenytoin and/or phenobarbital administration, plasma copper, zinc, and ceruloplasmin levels were measured in two groups of patients with developmental disorders who were either living at home (study 1) or institutionalized (study 2). Plasma copper and zinc levels were measured using an atomic absorption spectrophotometric method, and ceruloplasmin levels were determined using a method measuring oxidase activity (study 1) and an immunodiffusion plate method (study 2). In both studies, the mean plasma copper and ceruloplasmin levels of the anticonvulsant groups were significantly higher than those of control groups, while the mean plasma zinc levels for the anticonvulsant and control groups were similar. Possible change in the tissue zinc/copper ratio among the patients receiving long-term anticonvulsants is discussed.