A doctor accused of performing unlawful euthanasia at Kawasaki Kyodo Hospital in Kanagawa Prefecture in 1998 gave three shots of sedatives to a comatose male patient but wrote that they did not have any effect, medical records show.

The doctor then administered a muscle relaxant to the 58-year-old patient, who died shortly afterward, according to the medical records made public by the city of Kawasaki on Monday, after officials inspected the hospital.

"It is questionable to administer sedatives, which reduce breathing, to a patient having respiratory difficulty," a municipal official said.

The hospital said medical records show no other cases of the doctor in question administering muscle relaxants to patients who died in the past five years, the period when the doctor worked at the hospital.