Merck (NYSE:MRK) announced today that it is taking steps to suspend the availability of Tredaptive, a cholesterol drug that is less effective and has more potential side effects than previously expected. The drug, extended-release niacin/laropiprant, is not sold in the U.S.

After receiving a recommendation from a European medical regulatory agency, the pharmaceutical company is officially recommending physicians stop prescribing Tredaptive.

Merck Chief Medical Officer Dr. Michael Rosenblatt was quoted in a company press release as saying: "Patients currently taking Tredaptive are our priority, and we are committed to continue to work with regulatory agencies around the world to ensure that physicians have appropriate information as we take steps to suspend the availability of Tredaptive."

Although the drug is not approved for use in the U.S., it is currently approved in approximately 70 countries and sold in about 40 countries. At the time of the company's last quarterly report in November, Merck had planned to file applications for U.S. and EU approval in 2013. For the first three quarters of 2012, sales of the drug were approximately $13 million.