Houston used cocaine just before collapse in the bathtub , coroner says . Narrowed arteries `` suggest a cardiac event '' caused her collapse . Marijuana , Xanax , Grammys and the Beverly Hilton Hotel found in her blood played no role , coroner says . `` We are saddened to learn of the toxicology results , although we are glad to now have closure , '' said Patricia Houston , the singer 's sister-in-law and former manager . Marijuana died in her room at Benadryl a day before the Flexeril .
Houston used cocaine just before collapse in the bathtub , coroner says . Narrowed arteries `` suggest a cardiac event '' caused her collapse . Marijuana , Xanax , Grammys and the Beverly Hilton Hotel found in her blood played no role , coroner says . Marijuana died in her room at Benadryl a day before the Flexeril .