Study of vitamin D serum level in patients with epilepsy treated with enzyme-inducing and non enzyme-inducing medications

Changes of serum minerals and vitamin D have been reported in anticonvulsant drugs user patients. The present study aimed at comparing the changes of serum minerals and vitamin D among two groups of enzyme-inducing and non enzyme-inducing anticonvulsant drug users.

In this study 22 patients treated with enzyme-inducing drugs (carbamazepin، phenytoin، phenobarbital) were compared to 25 patients of matched sex، age، and BMI treated with non enzyme-inducing drugs (sodium evaporate، lamotrigine). Serum calcium، phosphate، parathormone، and 25-hydroxy vitamin D were calculated in both groups. Calcium was measured by Calorimetery method. Parathormone and vitamin D were measured using ELISA method.

The mean serum vitamin D level was lower in enzyme-inducing than non enzyme-inducing drugs users (15. 9±8. 3 and 24. 2±14. 8، P=0. 02). Frequency of vitamin D deficiency was higher in enzyme-inducing compared to non enzyme-inducing drugs users، 84% and 48%، respectively (P=0. 016). The mean serum calcium level was significantly lower in enzyme-inducing drugs users. (8. 7±0. 2 vs. 9. 0± 0. 7، p= 0. 05). Four percent in enzyme-inducing group compared to twenty four percent of non enzyme-inducing group had secondary hyperparathyroidism (P=0. 016).

While vitamin D deficiency is more frequent in enzyme-inducing drug users، secondary hyperparathyroidism is less frequent.