seizure

A 28-year-old man with bipolar disorder, who is on lithium, is found in his room 2 days after not showing up to work. He is arousable but dysarthric and has a markedly abnormal gait when trying to walk. Upon arrival at the emergency department, he has a grand mal seizure (type). The seizure is not sustained but recurs an hour after 6 mg lorazepam is infused IV. In the postictal stage, he is not arousable to sternal rub and lacks a gag reflex. His serum sodium returns at 158 meq/L. In reference to his seizures, all of the following are next steps in his management except