<prompt> Lithium most commonly used in:Bipolar disorderDepressive disorderPersonality disorderHeadache  <response>: Ans. a Bipolar disorderRef.: Harrison 19th ed. 2717 DOC for prophylaxis of bipolar disorder- Lithium DOC for acute mania: Lithium Lithium can also be used in treatment of neutropenia and cluster headache and major depression episodes. Therapeutic level of lithium: 0.8 - 1.2 mEqL Toxicity seen after 1.5 mEqL Most common side effect of lithium: Tremor Lithium is contraindicated in 1st trimester of pregnancy. It can cause congenital heart defect- Ebstein anomaly. 