LAS VEGAS -- Boxer Johnny Tapia's condition was upgraded from critical to serious at a hospital here Sunday, a day after he fell down and lost consciousness.

A University Medical Center spokesman provided no further information other than the five-time world champion's condition had improved.

Tapia was admitted to hospital early Saturday morning after he was charged with possessing drug paraphernalia. He was placed on a respirator and was being treated for head trauma.

Tapia and his cousin were involved in a police standoff at a house near Bullhead City, Ariz., late Friday that ended with the arrest of two men and Tapia being given a citation for possession of drug paraphernalia.

Tapia, 35, returned to his Las Vegas home several hours after the confrontation with police and was with his wife, Teresa, when he fell, according to Trayce Zimmermann, Tapia's publicist.

Zimmermann said Sunday she had no additional details about what happened.

Tapia, who only two years ago was hospitalized for a drug overdose after attempting suicide, last fought Nov. 3 when he lost a 12-round decision to bantamweight Marco Antonio Barrera.