The 92-year-old politician was shifted to the Intensive Care Unit (ICU) of the Max Super Speciality Hospital here on October 26, as he was suffering from fever and pneumonia.
"Today his blood pressure dropped significantly and other health parameters also deteriorated. He has been put on life support," the doctor said.
A team of doctors is monitoring his condition in the ICU round the clock, he said.
The veteran leader, who has also served as a Union minister in several Congress governments and also as the Andhra Pradesh governor, is being treated under the supervision of senior neurosurgeon J D Mukherjee and senior cardiologist Sumit Sethi.