In an appeal for the public's help in stemming the epidemic of prescription drug deaths, the Medical Board of California is asking people whose relatives died of overdoses to contact the board if they believe excessive prescribing or other physician misconduct contributed to the deaths. Linda K. Whitney, the board's executive director, urged those with information about improper treatment to contact the board without delay. By law, the agency has seven years from the time of the alleged misconduct to take disciplinary action against a physician.