The payment settles charges brought by 45 state attorneys general, while California’s portion of the settlement is around $7.1m.
The settlement prohibits the UK drug-maker from providing incentive payments to its salespeople that encourages the use of drugs not indicated on their labels, and from using paid doctors to promote its products.
California attorney-general Kamala Harris said: "Patient care is undermined when pharmaceutical companies promote uses for drugs that have not been approved by the FDA or pay medical professionals to promote certain drugs. This settlement requires GSK to pay a significant penalty and imposes strong new rules designed to prevent future misrepresentations of GSK products."
The complaint and stipulated judgment that is submitted to the San Diego County Superior Court alleges that GSK violated state consumer protection laws by misrepresenting the uses and qualities of certain drugs.
Under the settlement, the company is also required to continue its Patient First programme at least through March 2019, reducing financial incentives for sales representatives who engage in deceptive marketing.
The settlement also needs scientifically trained personnel to be ultimately responsible for developing and approving responses to health care provider questions and for these responses to be unbiased and non-promotional.