Diurnal variation of serum copper and zinc in epileptics receiving anti-convulsants.

Serial measurements of copper and zinc concentrations in serum were made at 06.00, 14.00, 22.00 and again at 06.00 hours in 37 male patients with epilepsy, aged between 9 and 19 years. Anticonvulsant drugs were administered at 08.00 and 20.00 hours, and standard hospital meals were allowed at 07.30, 12.00, 16.00 and 19.00 hours. Similar to our previous results, eight patients (21.6%) had serum copper levels greater than the reference range (11.0-20.5 mumol/l) and this hypercupraemia was associated with carbamazapine and/or phenytoin medication. No diurnal variation in serum copper level was observed. Serum copper concentration had no correlation with either 24 h urinary copper excretion or serum anti-convulsant drug levels. Serum zinc concentrations were within the reference range (10-16.5 mumol/l), confirming our previous report. No relation with anti-convulsant medication or serum copper levels was found. Diurnal variations in serum zinc levels with peak and trough concentrations at 06.00 and 14.00 hours, respectively, were observed. It is proposed that these variations in serum zinc concentrations are a normal physiological process and is unlikely to be related to anti-convulsant drugs or epilepsy.