The state has revoked a Tooele doctor's licenses to practice medicine and to prescribe controlled substances based on allegations of negligence.

Grmislav Gregory Drezga, formerly an employee of the Tooele Valley Medical Center, had his licenses revoked by the Utah Division of Occupational and Professional Licensing effective Feb. 4 following an investigation and hearing before the Utah Physicians Licensing Board.The division's investigation documented at least five separate cases between February and May 1997 in which "Drezga's actions with patients constituted gross negligence or incompetence," a division press release said.