TRENTON, N.J.— Merck & Co. has agreed to pay $688 million to settle two long-running lawsuits brought by investors who alleged that the drugmaker delayed releasing bad news on its blockbuster cholesterol drugs to prevent a drop in sales.

Merck, the world’s third biggest drugmaker by revenue, said Thursday that it agreed to the settlement because it is in the best interest of the company and current shareholders. It is taking a charge of nearly a half-billion dollars against 2012 earnings.