Feb 15 (Reuters) - Drugmaker Merck & Co Inc said the U.S. Food and Drug Administration declined to approve its claim that cholesterol-lowering drugs Zetia and Vytorin reduce the risk of heart attacks and strokes in patients with coronary heart disease.

The company said that after receiving a complete response letter from the FDA, it will review the letter and determine its next steps.

Merck noted in a statement that both drugs are indicated to reduce LDL, or "bad," cholesterol, but "The effect of Zetia on cardiovascular morbidity and mortality has not been determined."

The company said the FDA determined that Vytorin, which is a combination of Zetia and the cholesterol drug simvastatin, has no additional benefit on cardiovascular diseases beyond those already been established for simvastatin.

The applications were based on the results of Merck's Improve-IT study.

The FDA's decision follows a recommendation in December by one of its advisory committees that Merck should not be allowed to claim that Vytorin reduces the risk of heart attacks and strokes in patients with coronary heart disease.

(Reporting by Kshitiz Goliya in Bengaluru; Editing by Leslie Adler)