Kenya's ousted Deputy President Rigathi Gachagua on Sunday lashed out at his boss William Ruto as "vicious" and cruel, warning that his life could be in danger.

Gachagua was impeached by the Senate on five out of 11 charges levelled against him on Thursday, but a court order put his replacement process on hold.

"I am shocked by how vicious a man I helped to be president, believed in and was persecuted when I supported could be so vicious against me," he told reporters.

The embattled 59-year-old said his security had been withdrawn and his entire staff sent on compulsory leave.

"If anything happens to me or my family, President William Ruto must be held to account," he said, claiming past attempts at his life.

He was speaking after he was discharged from a hospital in the capital Nairobi where he was being treated for severe chest pains.

Gachagua fell ill on Thursday barely an hour before he was due to testify in the unprecedented two-day impeachment trial.

The upper house proceeded to vote on his removal from his office after his lawyers unsuccessfully bid to postpone the session.

He was found guilty on charges including threatening judges and practicing ethnically divisive politics, but cleared of corruption and money-laundering.

In the fast-moving political drama, Ruto swiftly nominated Interior Minister Kithure Kindiki to replace Gachagua.

But a High Court in the capital suspended the appointment process within minutes of parliament voting overwhelmingly to approve Kindiki, a 52-year-old academic turned political heavyweight.

A three-judge bench is due to hear the case on Tuesday.

"The president in total violation of the court order viciously withdrew security around me," Gachagua said, despite him still being deputy president.

"I don't understand this level of viciousness... at his lowest moment in life when he is literally struggling to stay alive, you unleash such viciousness against him."

Ruto has not yet given any public comment on the impeachment.

Gachagua is the first deputy president to be ousted in this manner since impeachment was introduced in Kenya's revised 2010 constitution.