The recall covers the entire U.S. stock of Liptruzet, a combination drug which was only launched eight months ago.
Liptruzet combines two popular drugs that work in complementary ways to reduce levels of LDS, or bad cholesterol, a common strategy for prevent heart attacks and strokes.
The problem is the foil pouches holding the pills may allow air and moisture inside. Merck says there's a remote chance the packaging problem could decrease the drug's effectiveness, or change its properties.
There have not been any reports of patients being harmed.
The company, based in Whitehouse Station, N.J., said patients can continue taking any Liptruzet they have and should consult a doctor before stopping it.
Merck is working with the U.S. Food and Drug Administration to get Liptruzet back on the market as soon as possible.
Adverse reactions or problems with the use of this produced may be reported to the FDA's MedWatch Adverse Event Reporting program online at www.fda.gov/medwatch/report.htm or via phone by calling (800) 672-6372.
The Associated Press contributed to this report.