A certified emergency medical technician may perform any function consistent with his certification, according to guidelines and regulations that the board may prescribe. Emergency medical technicians, trained to provide advanced life support and possessing current Department of Health and Environmental Control certification while on duty with a licensed service, are authorized to possess limited quantities of drugs, including controlled substances, as may be approved by the Department of Health and Environmental Control for administration to patients during the regular course of duties of emergency medical technicians, pursuant to the written or verbal order of a physician possessing a valid license to practice medicine in this State; however, the physician must be registered pursuant to state and federal laws pertaining to controlled substances.