The first line drug for management of generalized tonic-clonic seizure is sodium valproate. It is used as monotherapy. Even though lamotrigine is equally effective, however, due to lower adverse effects profile of sodium valproate, it is used as first line pharmacologic agent in treatment of generalized tonic-clonic seizure. Reference: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5020233/#:~:text=Both%20valproic%20acid%20and%20lamotrigine,being%20more%20effective%20and%20safe. Video source: https://www.youtube.com/watch?v=goXXl4qYIUg