Vicodin isn't OTC...prescription only. It is a combination of hydrocodone and acetaminophen. It is a narcotic, so would make one feel high...giggly could certainly be part of it. Of course, narcotics depress the CNS, so can be very dangerous if used incorrectly. Overdoses can kill.

However, available OTC and frequently abused by kids are cough medicines containing dextromethorphan.

Here is a link explaining that, for any one interested.
www.drugfree.org/Parent/R...cine_Abuse

Good luck getting to the bottom of all this.