Mr Tiwari was shifted to the Intensive Care unit (ICU) of the hospital from the private ward on October 26 after fever and pneumonia.
His family also said the veteran politician's health continues to deteriorate. "Tiwari ji's blood pressure dropped significantly around 5 pm. His other health parameters also deteriorated. He has been put on life support," a family member told news agency IANS.
He said doctors termed Mr Tiwari's condition "extremely critical" and were continuously monitoring him in the ICU.
Mr Tiwari, a Congress veteran, was admitted to the hospital on September 20 after he suffered a brain stroke and a paralytic attack.
A senior doctor said the next 24 hours were extremely critical for Mr Tiwari. The veteran leader, a former Union Minister, has been the Andhra Pradesh Governor in the past. He is undergoing treatment from senior neurosurgeon J.D. Mukherjee and senior cardiologist Sumit Sethi.