[Hyperhomocysteinemia and treatment with antiepileptic drugs. Effects of different doses of folic acid].
BACKGROUND AND OBJECTIVE: An increase homocysteine values, which is an independent risk factor for atherotrombotic disease, can be produced with antiepileptic treatment. The aims of this study were: 1) to assess the frequency and determinant factors of hyperhomocysteinemia in adult patients receiving antiepileptic drugs, and 2) to know the effect of different doses of folic acid. PATIENTS AND METHOD: Ninety eight patients and 100 healthy controls similar in age and gender were studied. Eighty six patients were treated with hepatic enzyme inductors (diphenylhydantoine and/or phenobarbital and/or primidone and/or carbamazepine), 5 received non inductors (valproate) and 7 were treated with both in combination. Thirty eight patients were randomized to receive in an open and concurrent way folic acid, 0.2 mg (n = 18) or 5.2 mg (n = 20) daily for 3 months. RESULTS: Homocysteine values were increased in patients in relation with controls (mean [SD]12.2 [6.7] 95% confidence interval [CI],10.0-13.5 vs 8.8[2.2] 95% CI, 8.3-9.2 micromol/l; p < 0.001). Hyperhomocysteinemia was found in 28 patients and 4 controls (28.6% vs 4.0%; p < 0.001). In a multivariate analysis hyperhomocysteinemia was positively associated with treatment with antiepileptic inductors and negatively with folate values and female gender. Homocysteine values decreased after treatment with folic acid at high and low doses (p < 0.001 for both groups), and the values observed in the latter group were similar to those in healthy controls. CONCLUSIONS: Hyperhomocysteinemia is frequent in patients treated with antiepileptic drugs. Treatment with hepatic enzyme inductors and low folate values are predictors of hyperhomocysteinemia. Administration of folic acid, even at very low doses, produces a significant decrease of homocysteinemia in these patients.