In a City Hall courtroom this week, Pennsylvania is trying to convince a Philadelphia jury that it was duped into overpaying $160 million for the antipsychotic drug Risperdal.

The state, which provided the drug to the poor and elderly, wants to be reimbursed by Janssen Pharmaceutica Inc., a subsidiary of Johnson & Johnson, maker of Risperdal.

Pennsylvania contends that Janssen falsely claimed Risperdal was safer and more effective than similar but less expensive antipsychotic drugs, such as haloperidol, also known as Haldol. As a result, the state says it paid millions of dollars in unnecessary premiums for Risperdal.

According to Fletch Trammell, attorney for Pennsylvania, the state was paying as much as $13 a pill for Risperdal, as opposed to 50 cents per tablet for comparable medication.

"There were a dozen antipsychotics that were just as good as Risperdal and cost a fraction" as much, he told the jury in his opening statement last week.

Janssen has denied misleading Pennsylvania about Risperdal.

"Janssen has always been committed to ethical business practices," Greg Panico, a spokesman for Janssen, said in a written statement. "We are fully prepared to defend against these claims, which we think are without merit."

The case is among numerous claims that have been brought against Janssen for allegedly marketing Risperdal to treat conditions for which the drug had not been approved, or for allegedly understating its shortcomings.

The drug was part of a new generation of antipsychotics introduced in the early 1990s to treat severe mental illnesses, such as schizophrenia and bipolar disorder.

Over time, Risperdal was also prescribed for a variety of other ailments for which it had not been approved, including dementia, aggression, and behavior problems.

Such unapproved applications for a drug are known as "off-label uses." They are acceptable if prescribed by doctors. The drug manufacturer, however, is not permitted by the FDA to market products for off-label uses.

Although some states are accusing the company of off-label marketing, that is not part of Pennsylvania's case.

One twist in the case is the Rendell administration's decision to use the Texas firm Bailey, Perrin, Bailey L.L.P. to represent the state on a contingency basis. Bailey's founder, F. Kenneth Bailey, made more than $91,000 in campaign contributions to Gov. Rendell. Rendell has denied any impropriety. Janssen has asked the state Supreme Court bar the state from using the Texas firm. The court has not ruled yet on the request.