Modified release formulations of HMG Co-A reductase inhibitors, which provide reduced incidence of rhabdomyolysis, renal toxicity and other side effects by increasing hepatic bioavailability and decreasing systemic availability upon oral administration. The modified release pharmaceutical formulation comprises a therapeutically effective amount of HMG CoA reductase inhibitor or a pharmaceutically acceptable salt(s), polymorph(s), solvate(s), hydrate(s), prodrug or metabolite thereof, one or more release modifying agent(s) and one or more pharmaceutically acceptable excipient(s), wherein the modified release formulation provides reduced incidence of adverse effects and improved efficacy when compared to the immediate release formulation upon oral administration.