WASHINGTON (AP) - Federal advisers said Wednesday that a longer-lasting version of Eli Lilly's best-selling drug Zyprexa is safe and effective for the treatment of schizophrenia.

The FDA's panel of psychiatric experts voted 10 to 0 that the company's Zyprexa Adhera, an injectable version of the Lilly drug, appears safe.

Zyprexa is currently available as a once-daily pill to treat schizophrenia and bipolar disorder. The new formulation is injected into the muscle and designed to last two to four weeks.

The panel's recommendation is good news for Lilly in a month that's seen little of it on the Zyprexa front. The New York Times recently revealed that the drug company was in confidential settlement discussions with federal prosecutors who are investigating improper marketing of the antipsychotic.

FDA scientists said earlier this week that while the new version appears to work, a small number of patients experienced extreme sedation while taking the drug.

The FDA's panel is scheduled to vote Wednesday afternoon on whether the drug should carry warnings about the sedation, possibly including a ‘‘black box'' warning, the most serious a drug can carry.

Lilly still faces lawsuits from several states, and some third-party payers accusing it of promoting the ‘‘off-label'' use of Zyprexa for treatments not approved by the FDA.

Zyprexa was Lilly's top-selling drug last year. It rang up $4.8 billion and accounted for 25 percent of the company's total sales, but it also has brought the company many legal headaches.

Lilly representatives deny promoting the off-label uses.