A 36-year-old man with bipolar I disorder is brought to the psychiatric emergency department by his spouse. Over the past five days he has slept a total of approximately eight hours, has spent $14,000 on cryptocurrency investments using credit cards, is speaking rapidly and jumping between business ideas, and believes he has a unique ability to predict market trends. He is irritable when challenged but not overtly aggressive. His current medications include lamotrigine 200 mg daily, which was initiated eight months ago for bipolar depression maintenance. Vital signs are stable and urine drug screen is negative. His Young Mania Rating Scale score is 32. The PMHNP is developing a treatment plan for this acute manic episode. Which of the following is the most appropriate approach?