What Is The Right Dosage Of Concerta To Be Given To Children?

Hello, my son took 18mg of concerta, too late in the day I think, about 12 pm, it s now 9:23 and still very hyper how can I counteract the drug so he can calm down and sleep, he s 9, and today was his first day, I know odds are against me, and I should ve started the drug the next day in the early am, just asking, Thanks.. Any hope for sleep tonight?