Practice question

A 33-year-old man with known bipolar I disorder is brought to the emergency department by his family due to a 1-week history of elevated mood, decreased need for sleep (sleeping 2 hours a night), pressured speech, and grandiosity. He has been spending excessively and making impulsive decisions. He is currently not on any regular medication. What is the most appropriate initial pharmacological management for his acute manic episode?