This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pharmacology
Visual field monitoring is impoant before staing? 
Select and explain. 
A. Vigabatrin, B. Topiramate, C. Valproic acid, D. Carbamazepine
A: Vigabatrin
Answer: A: Vigabatrin 
Explanation: Ans. is 'a' i.e., Vigabatrin o Vigabatrin is an irreversible inhibitor of GABA transaminase, thus increases GABAergic activity. It is the DOC for infantile spasms (previously ACTH was DOC). It can result in irreversible visual field defects due to retinal atrophy. Therefore visual field monitoring is impoant.