This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: C.N.S, Subject name: Pharmacology
Drug of choice for bipolar syndrome: 
Select and explain. 
A. Lithium, B. Imipramine, C. Phenytoin, D. Clozapine
A: Lithium
Answer: A: Lithium 
Explanation: Ans. A. LithiumLithium is mood stabilizer which is drug of choice for bipolar syndrome. It has narrow therapeutic index. (8-1.2ng/dl). It is known to cause tremor, nephrotoxicity, hypothyroidism and Ebstein anomaly. Other drugs like SSRI, valproate, carbamazepine, lamotrigine can also be given in bipolar disease.