Hospira Pharmaceuticals, the only American manufacturer of a drug used in U.S. executions, will cease making that drug, the company announced today.

Sodium thiopental, an anesthesia drug, is used to put inmates to sleep before two other drugs paralyze the muscles and stop the heart. There has been a shortage of sodium thiopental recently, forcing states to scramble for alternatives or delay executions. Hospira said a supply issue with the drug's active ingredient was to blame for the shortage. [Read Execution Science: What's the Best Way to Kill a Person?]

The company had planned to move manufacture of the product, known as Pentothal, from North Carolina to its plant in Italy. Hospira spokesman Daniel Rosenberg told LiveScience the move was because the Italian facility had a state-of-the-art sodium thiopental production line. But Italian authorities objected to the drug's use in executions and insisted that Hospira prevent the drug's use in capital punishment. (Italy does not allow the death penalty.)

The Italian negotiations were not a contributing factor to the drug's previous shortage, Rosenberg told LiveScience.

Hospira has regularly voiced its own disapproval of the drug's use in the death penalty, arguing that it is a drug with legitimate medical uses. The company sells primarily to wholesalers, and said in a statement that it cannot control how customers use the drug.

"Based on this understanding, we cannot take the risk that we will be held liable by the Italian authorities if the product is diverted for use in capital punishment," the statement read. "Exposing our employees or facilities to liability is not a risk we are prepared to take."

The cease in manufacturing is likely to cause more difficulties for states trying to execute prisoners. All of California's supply of sodium thiopental expired Oct. 1. Arizona, Kentucky, Ohio and Oklahoma have also experienced sodium thiopental shortages. On Dec. 16, Oklahoma inmate John David Duty became the first person in the United States whose execution involved pentobarbital, a drug usually used to euthanize animals.

You can follow LiveScience Senior Writer Stephanie Pappas on Twitter @sipappas.