Jack Blades, 16, of Airdrie, North Lanarkshire, collapsed at a house party and his family had been keeping a bedside vigil as he remained seriously ill in the town's Monklands Hospital.
His sister Lauren wrote on her Facebook page: "My baby bro is awake and has a smile on his face already!! Could not be happier right now."
Detectives arrested a 16-year-old boy in connection with the incident. He was later freed from custody pending further inquiries.
Mortal Kombat pills feature the image of a dragon.