Michael Anderson, 19, has been jailed in Catawba County on murder charges since the body of Stephen Starr, 36, was found in Starr's Mountain View home Monday, The Charlotte Observer reported.
Authorities say Anderson called 911 early Monday and said, "I shot him three times and then I used an axe and mutilated his body."
The caller said he had taken Mucinex DM, an over-the-counter cough suppressant that contains dextromethorphan, and "the pills made me go mad."
The Food and Drug Administration has warned that abuse of the drug can lead to hallucinations and psychotic episodes.
A word was carved into Starr's body, but authorities would not disclose it.
The caller said he met Starr at a gay club, and Starr made sexual advances.
On a Facebook page listed for Michael Joseph Anderson, a posting just before the 911 call read,
"I WOULD RATHER WANT TO KILL ALOT MORE YOU KNOW BUT OH WELL ONE WILL DO I GUESS..."
Neighbor Barry Leatherman told Charlotte's WCNC-TV he met Anderson Saturday, when Starr introduced him as his adopted son.