FDA warns King Pharmaceuticals on Avinza promo

WASHINGTON (Reuters) - U.S. health officials have warned King Pharmaceuticals Inc that promotional material for its pain drug Avinza fails to warn consumers about the potential for abuse.

According to a letter from the U.S. Food and Drug Administration, the company failed to include any information about possible abuse of the drug -- a controlled substance -- and made unproven claims about how well it worked.

"The combination of such broad and unsubstantiated efficacy claims about the benefits of Avinza and the omission of the serious, potentially fatal risks associated with its use, as well as its potential for abuse, is especially egregious and alarming in its potential impact on the public health," it said.

The agency posted the March 24 letter on its Web site on Tuesday as part of its weekly update on companies, doctors and others who have drawn warnings from the agency.

Avinza, known generically as morphine sulfate, is approved to treat chronic moderate-to-severe pain in patients who need continuous relief for a longer period of time.

In the letter, the FDA said the drugmaker's 22-page promotional material also implied that Avinza could be used by a broader group of patients.

Representatives for King, which acquired the drug from Ligand Pharmaceuticals Inc in 2007, did not immediately return calls seeking comment.

Shares of King were not negatively affected by the letter, which was posted elsewhere on the FDA Web site last week. Its shares were up 4 percent, or 35 cents, at $9.05 in morning trade on the New York Stock Exchange.

(Reporting by Susan Heavey, editing by Gerald E. McCormick and Steve Orlofsky)