May recalls

A 3-year-old is brought in after a brief self-limiting seizure; he is now postictal and the bedside glucose is 2.2 mmol/L. He has had a viral illness with poor oral intake and vomiting over the past day, and his parents say he seemed increasingly lethargic and sweaty before the seizure started. He is now drowsy but rousable, with stable vital signs. What is the best immediate treatment?