An Ohio woman claims that long-term use of AstraZeneca's Nexium, a heartburn drug, caused such severe bone deterioration that she "was simply walking when a bone in her leg suddenly broke in half." 

Nexium is AstraZeneca's best-selling drug and the third largest-selling drug in the world, bringing in $5.2 billion in 2008.

In her suit filed in U.S. District Court in Houston, Ginny Begin of Toledo says she suffered severe bone deterioration resulting in numerous fractures after taking Nexium, a popular prescription-strength drug used to treat heartburn, acid reflux and other digestive problems.

However, while Nexium reduces acid in the stomach, it also prevents calcium absorption, which casues bone deterioration and eventual fractures, her suit charges.

The suit noted that the U.S. Food and Drug Administration issued a safety alert warning of the risk of osteoporosis and fractures in March 2011 but says that the risk of fractures had been demonstrated as early as 2006.

In particular, the suit notes, studies found that the risk of fracture increases significantly for patients over 50. Begin, 58, took Nexium every day from 2003 until 2011, she said.

On July 11, 2005, Begin was "simply walking" when a bone in her leg suddenly broke in half. In June 2007, the same bone broke again and three bones in Begin's ankle shattered.

"Despite knowing Nexium causes bones to deteriorate and break, Defendants marketed and sold Nexium without warning consumers of the significant risks of bone deterioration and fractures," the suit charges.

The suit seeks an award for pain, suffering, loss of employment, medical expenses and punitive damages.