A Utah woman who allegedly broke her ex-husband's legs after smashing her 4WD into an office building has blamed the anti-anxiety drug Xanax for her actions.

Dramatic video captured on surveillance cameras shows 26-year-old Brenda White allegedly ramming her Ford Explorer car into the foyer of the building, knocking her former husband, John White, to the ground, US network ABC News reports.

"This SUV just drove into our building," a caller told a 911 dispatcher.

"[The driver is] chasing some guy down. The car is all the way inside the building. [The driver] went through, going like 70 miles an hour."

Mr White was treated in hospital for two broken legs and required 63 stitches over his legs, arms and face.

Mrs White was arrested and charged with attempted murder over the 2006 incident. She was later released on $500,000 bail.

The pair were going through what police described as an "ugly divorce" at the time.

Lawyers for Mrs White say she was "not in her right mind" during the attack and argue that she had taken too much Xanax which was partially to blame for the incident.

On rare occasions Xanax can cause outbursts of anger, delusions and aggressive behavior.

Mrs White has since apologised for the attack, but claims she does not remember the incident.

Asked what she recalled about the alleged attack a sobbing Mrs White told the court: "I don’t. [Being in the parking lot] is the last thing I remember. The next thing I remember, I was inside a building," the Salt Lake Tribune reports.

"It was not me. Jon was my husband. He was my best friend, my lover. I would not want to hurt him," she said.

Sources: Salt Lake Tribune, ABC News

Author: Emily O'Keefe. News editor: Henri Paget