UPDATE 1-Baxter lung drug promotion misleading -- US FDA

* Baxter made misleading claims about Aralast

* Drugmaker given earlier warnings about similar issues

* Company shares fall slightly

WASHINGTON, Aug 31 (Reuters) - U.S. health officials have issued a warning to Baxter International Inc (BAX.N) for misleading patients and doctors about the benefits of its Aralast lung drug.

In the warning released on Tuesday, the U.S. Food and Drug Administration said a company brochure made misleading claims about the drug, which treats emphysema patients with a specific genetic abnormality.

The FDA warned Baxter about similar violations in April 2009 and July 2008.

"We are very concerned by your continued violative promotion of your products," the FDA wrote.

In the brochure, Baxter misleadingly implied the drug had a protective effect, even though the clinical benefit for certain effects of the drug have not been shown, the FDA said.

Baxter said in a statement it took the FDA's concerns seriously and has put the brochure on hold.

Baxter shares fell 0.4 percent to $43 in midday trading on the New York Stock Exchange.

The FDA posted the letter, dated Aug. 3, on its website at link.reuters.com/qex48n (Reporting by Lisa Richwine and Susan Heavey; editing by Andre Grenon)