Had left half of an 40mg Oxycontin pill on my night stand! Came back about an hour later and was unable to locate pill! Time was approximately 5:00 PM! 4 to 4 1/2 hours later, younger stepsister, age 8, strangely says she took pill by accident! What would the side effects be to someone of that age and how long would it take them to take effect on her?