The effects of the antiepileptic drugs on thyroid hormons and blood biochemistry

The effects of the antiepileptic drugs on hormons, lipid and lipoprotein metabolisms and the levels of the vitamin B12 and folate have been well verified. But these studies were about old antiepileptics which are enzyme inhibitors and inductors. There are very limited numbers of studies about the same subject of the ?new? antiepileptics, up to this date. Growing numbers of epileptic patients are using new antiepileptics these days. The new antiepileptics have superior features like low side-effect profile and drug-drug cross reactivity. In this study, antiepileptics like valproic acid and carbamazepine were compared with new antiepileptics such as oxcarbazepine, levetiracetam and topiramate about the effects on thyroide hormons, lipid profile, serum levels of folic acid and vitamin B12.Patients with partial epilepsy were recuited for the study. They were epileptic patients for at least one year in antiepileptic drug regimen. Total number of 63 patients; 15 for carbamazepine, 15 for valproic acid, 15 for oxcarbazepine, 9 for levetirasetam and 9 for topiramate were arranged in different drug groups. Two different control groups, first as healthy (n=15) and second as epileptic but no use of drugs (n=15) were gathered.Results of the healthy controls and the epileptic controls were compared. Serum triglicerid and VLDL were high (P<0,05), AST was low (P<0,05) and the levels of folic acid were low ((P=0,001) in the epileptic controls. Patients on carbamazepine were compared with the healthy controls; carbamazepin group has higher total cholesterol (P<0,05) and lower folic acid levels (P<0,05) than the healty ones. The same comparison with the epileptic group yielded high HDL levels in patients on carbamazepine (P<0,05). When patients on valproic acid compared with the healthy controls; AST and ALT levels were low (P<0,05) and folic acid was low(P<0,001) in the valproic acid group. When compared with the epileptic group, there were low levels of vitamin B12 (P<0,05) in the vaproic acid group. In comparison of oxcarbazepine group with the healthy controls; FT4 (P<0,05) and folic acid (P=0,001) were low and total cholesterol was high (P<0,05). When compared with the epileptic group higher HDL and AST (P<0,05) levels. İn levetiracetam group higher total cholesterol, vitamin B12 and lower folic acid levels (P<0,05) than healthy controls. In comporison with the epileptic controls, there was no difference in statistical significance. The topiramate group had lower levels of AST and folic acid (P<0,05) in comparison with the healthy controls but lower triglicerid (P<0,05) and higher HDL (P<0,05) when compared with the epileptic controls.Result of our study suggested that the new antiepileptics have no negative effects on thyroid hormones, vitamin B12, folic acid and liver enzymes. Besides, they have anti-atherosclerotic effects on lipid profile. There are some evidence of their favorable effects on coronary health patients in literature. Some observed pathological effects were found as statistically insignificant in comporison with epileptic control patients. These findings suggest that some negative effects in relation with use of antiepileptics frequently mentioned in the literature are the result of the epileptic processes itself; yet undetermined. Possibly, they have not been related to the use of antiepileptic drugs.Key words: Antiepileptic, Folic acid, Vitamin-B12, Thyroid, Lipid