U.S. drug regulators are changing the label for Merck & Co Inc’s recently approved Victrelis treatment for hepatitis C to show it should not be taken with some widely used HIV medicines. “Co-administration (of the two drugs) ... is not recommended at this time because of the possibility of reducing the effectiveness of the medicines, permitting the amount of HCV (hepatitis C virus) or HIV ... in the blood to increase,” the U.S. Food and Drug Administration said on Thursday. The FDA and Merck first warned about the issue in February based on the results of a drug interaction study, but a label change could further crimp sales of Victrelis.
