thromboplastin and Epilepsy

Valproic acid (VPA) is an antiepileptic drug that has been associated with impaired hemostasis and increased risk for postsurgical bleeding. However, the published reports provide controversial results. We measured parameters of primary hemostasis in VPA-treated patients with epilepsy, focusing on adenosine nucleotide-dependent platelet responses, which play a central role in primary hemostasis. We enrolled 20 cases (epileptic patients receiving treatment with VPA) and 20 controls (12 epileptic patients receiving treatment with drugs different from VPA and 8 healthy subjects). Measurements included prothrombin time (PT), activated partial thromboplastin time (APTT), platelet count, platelet function analyzer (PFA)-100 closure times, plasma von Willebrand factor levels, platelet content of ADP, ATP, and serotonin (all stored in platelet dense granules), and platelet shape change and aggregation induced by ADP and other platelet agonists, including the ATP analog α,β-methylene-ATP. The plasma concentration of VPA was in the therapeutic range in 17 patients and slightly above the upper limit in 3 patients. There were no statistically significant differences in any of the studied parameters in cases versus controls. Our thorough controlled study failed to show that chronic treatment with VPA induces significant abnormalities of coagulation and primary hemostasis. Therefore, VPA, when present in the circulation in the therapeutic range, does not impair hemostasis.

Topics: Adenosine Diphosphate; Adenosine Triphosphate; Adolescent; Adult; Anticonvulsants; Blood Coagulation Disorders; Case-Control Studies; Child; Drug Administration Schedule; Epilepsy; Female; Hemostasis; Humans; Male; Platelet Function Tests; Prothrombin; Serotonin; Thromboplastin; Time Factors; Valproic Acid; Young Adult

The hemostasis function was studied in 33 patients with epileptical seizures of a different etiology. The studies were conducted at the moment of the epileptical seizure or epileptical status and in the interattack period during hyperventilation. The concentration of products of blood fibrinogen degradation, the degree of platelet agregation, their number and prothrombine index were estimated. The data obtained were compared with those of normals. The results of the studies indicate the existence of the syndrome of intravascular coagulation during an epileptical seizure and epileptical status.

Topics: Blood Cell Count; Blood Platelets; Cerebral Hemorrhage; Disseminated Intravascular Coagulation; Epilepsy; Fibrin Fibrinogen Degradation Products; Humans; Intracranial Embolism and Thrombosis; Male; Platelet Aggregation; Status Epilepticus; Thromboplastin