The government on Friday announced its second civil fraud lawsuit against Novartis AG in four days, accusing a unit of the Swiss drugmaker of paying multi-million dollar kickbacks to doctors in exchange for prescribing its drugs.

U.S. Attorney Preet Bharara in Manhattan said the government joined a whistleblower lawsuit that had been filed against Novartis Pharmaceuticals Corp in January 2011, and which seeks triple damages under the federal False Claims Act.

The government accused Novartis of causing the Medicare and Medicaid programs to pay millions of dollars in reimbursements based on kickback-tainted claims for drugs such as hypertension drugs Lotrel and Valturna and diabetes drug Starlix.

On Tuesday, the government accused Novartis of inducing pharmacies to switch thousands of kidney transplant patients to its drug Myfortic in exchange for kickbacks disguised as rebates and discounts. Novartis disputed those claims.

Novartis did not immediately respond on Friday to requests for comment.

(Reporting by Jonathan Stempel in New York; Editing by Gerald E. McCormick)