This article presents a clinical case of the antiepileptic drug effect on the Vitamin D rate (namely, the patient has been taking Sodium Valproate for a long time) and new data from the foreign publications on this problem. It is known that there is a list of drugs that adversely affect the Vitamin D metabolism. In particular, the drugs reducing the Vitamin D absorption include drugs for the treatment of epilepsy. Antiepileptic drugs are drugs of va­rious origins that are used to prevent or reduce seizures, their corresponding conditions (loss or impairment of consciousness, behavioral and autonomic disorders, etc.), which are observed with recurrent seizures of various forms of epilepsy. The widespread use of these drugs in medical practice requires a detailed study of possible side effects of these drugs and their timely correction, as foreign sources indicate that antiepileptic drugs increase Vitamin D deficiency and worsen the symptoms of proximal myopathy, requiring mandatory medical correction; patients with epilepsy are deficient in vitamin D; сhronic Valproate therapy is associated with lower bone mineral density in young patients with epilepsy. This clinical case showed how a long-term use of Sodium Valproate led to the development of secondary systemic osteoporosis and Vitamin D deficiency, as evidenced by the results of laboratory and instrumental studies, and the discontinued antiepileptic drugs along with Vitamin D supplementation improved the general health of the patient and Vitamin D blood rates. Based on the systemic review and our own observations, it has been conclu­ded that epilepsy patients taking antiepileptic drugs should be gi­ven Vitamin D supplements to prevent the development of osteoporosis and Vitamin D deficiency.