Former Bolivia interim president Jeanine Anez on Tuesday accused authorities of injecting her with a dangerous substance in prison where she is being held in pre-trial detention.

She was detained 10 days ago on charges of leading a coup against her socialist predecessor Evo Morales.

Anez was handed six months of pre-trial detention, but last week she petitioned authorities to release her to a clinic to receive treatment for a "hypertension crisis."

"I don't trust the government's doctors. They're part of the system of abuse and repression and have shown they're prepared to risk my life, injecting me with high risk medication without precautions or previous studies, with the only aim of keeping me in their cells," said Anez in a written note.

She did not explain what medication she was given, nor for what purpose.

A representative of the United Nations High Commissioner for Human Rights in Bolivia went to the La Paz women's prison over the weekend to verify the conditions in which Anez is being held, but has not yet commented.

Conservative Anez is accused of terrorism, sedition and conspiracy alongside her former justice and energy ministers, whom are also being held in pre-trial detention.

Bolivia's former interim president Jeanine Anez speaks with her lawyers from a jail cell on March 13, 2021
Bolivia's former interim president Jeanine Anez speaks with her lawyers from a jail cell on March 13, 2021 AFP / LUIS GANDARILLAS

Prosecutors on Tuesday accepted four new charges against her filed by the justice ministry in the name of the Bolivian government.

Anez is accused of issuing unconstitutional presidential decrees, failing to fulfill her duties, crimes against public health and discrimination.

"In this preliminary stage we have 30 days to carry out the corresponding investigations," an official said.

Anez described the governing Movement for Socialism (MAS) party of Morales and President Luis Arce as a "dictatorship" and insisted "there was no coup, there was fraud."

Anez, 53, came to power in November 2019 after Morales and several senior MAS allies resigned following weeks of protest over his controversial reelection to an unconstitutional fourth term.

As Morales fled into exile, Anez was the most senior parliamentarian left and was sworn in by Congress as the interim president despite the lack of a quorum.

But the MAS party is back in power since Arce romped to victory in last November's general election.

The United States has expressed "concern" about Anez's arrest while the OAS has demanded her release and questioned the impartiality of Bolivia's courts.