Johnson & Johnson has been ordered by a US judge to pay $US1.1 billion for downplaying the risks involved in taking Risperdal, an anti-psychotic drug.
The state of Arkansas sued J&J and its subsidiary Janssen Pharmaceuticals over its marketing of the drug in 2007.
A number of US states have already found the companies guilty of similar charges and fined them accordingly.
Janssen said it would appeal the fine if a motion for a retrial was denied.
In January, J&J agreed to pay $158 million to settle accusations of illegal marketing of Risperdal in Texas.
Last year, a South Carolina judge ruled the company must pay a penalty of $327 million after a jury found it guilty of similar charges, while in 2010, a Louisiana jury found the company violated the state's Medicaid fraud act.
The BBC reports these two verdicts are currently under appeal.
