The dehydration statement could be looked at cynically, but it does make a lot of sense, considering that Merriman was tweeting like crazy from the club and throughout the hours following his hospitalization. "That's absurd ... if you had a drug overdose, you wouldn't be at a club right after," Merriman's rep told TMZ.
I'm not expert in either dehydration or overdoses, but one seems much more conducive to using Twitter than the other. (Hint: it's not the overdose.)