A cancer patient died at a Tokyo hospital in December after a physician prescribed three times the required dosage of a chemotherapy drug, hospital officials said Thursday.

The 64-year-old Tokyo man, who was being treated for stomach cancer, died of multiple organ failure and blood poisoning Dec. 28 at the Cancer Institute Hospital in Tokyo’s Toshima Ward, about two weeks after checking into the facility, the officials said.

The hospital has admitted a 36-year-old physician prescribed an overdose of the anticancer drug, but it attributed the patient’s death to a combination of the overdose and the progression of the cancer.

The officials said they did not report the case to police because the man’s family did not wish to do so. They also said they did not inform the family about the overdose until March.

According to the officials, the man was hospitalized Dec. 15 with terminal cancer and given chemotherapy treatment.

His physician ordered one of the drugs to be administered over three consecutive days beginning Dec. 17, although it was supposed to be given on one day only.

The pharmacy department staff who prepared the doses based on the doctor’s prescription written on the patient’s medical chart did not notice the mistake, the officials said.

The patient began complaining of nausea on Dec. 20 and suffered a dramatic loss of strength, but the doctor did not realize the mistake until abnormal effects, such as a deterioration in the man’s liver functions, were observed, they said.

The physician then administered treatment for the overdose, but in vain, the officials said. The patient’s death was reported to the director of the hospital on Dec. 31.

A panel set up in January to study potential mishaps at the institution reported on the case, the officials said.

“It was simply a mistake in filling in the chart,” said Katsuhiko Hasumi, a panel member and a director of the hospital’s obstetric and gynecology department.

Patients’ medical charts list the days of a week and include rows on which physicians handwrite the names of drugs prescribed to patients. They then put circles in boxes corresponding to which days of the week the medication should be administered.

The cancer patient was receiving seven drugs and his physician marked the anticancer agent in question to be administered Friday, Saturday and Sunday, rather than only Friday, the officials said.

They said the doctor probably mistook the drug for the one written on the row above it.

“It is extremely unfortunate that a secondary check was not performed after the doctor made the careless mistake,” Hasumi said. “We hope to inspect the information gathered on this case carefully and make efforts to prevent medical mishaps.”