AstraZeneca PLC has agreed to pay $520 million to settle charges that it illegally marketed its schizophrenia drug Seroquel for unapproved uses, U.S. authorities said on Tuesday.

The U.S. government accused the company of promoting the drug to patients suffering from Alzheimer's diseases, anxiety, dementia, depression and post-traumatic stress disorder even though the Food and Drug Administration had not approved it for those uses.

As a result, false claims to pay for the drug were submitted to U.S. government healthcare programs, the Justice Department and Department of Health and Human Services said.

Further, the government accused AstraZeneca of violating anti-kickback laws by paying doctors to sign articles that the company wrote about the drug.

Additionally, the government accused the company of paying travel costs for doctors who consulted on marketing related to the unapproved uses of the drug.

In addition to the $520 million payment, AstraZeneca agreed to a program to ensure compliance with U.S. laws and will have to send a letter to doctors about the settlement.

The settlement formalizes an agreement that the British pharmaceutical company had reached in principle in October. It made provisions for the payment last year.

(Reporting by Jeremy Pelofsky. Editing by Robert MacMillan)