Diurnal Variation of Serum Copper and Zinc in Epileptics Receiving Anti-Convulsants
1 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. Anti-convulsant 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. 2 Similar to our previous results, eight patients (21.6%) had serum copper levels greater than the reference range (11.0–20.5 μmol/l) and this hypercupraemia was associated with carbamazapine and/or phenytoin medication. 3 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. 4 Serum zinc concentrations were within the reference range (10–16.5 μmol/l), confirming our previous report. No relation with anti-convulsant medication or serum copper levels was found. 5 Diurnal variations in serum zinc levels with peak and trough concentrations at 06.00 and 14.00 hours, respectively, were observed. 6 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.