WASHINGTON (April 14, 2012): Two Merck drugs for treating male baldness and enlarged prostate will now carry extended labels to add more possible sexual side effects, US regulators said. The changes involve Propecia and Proscar, both of which contain the active ingredient finasteride, after patients reported additional adverse effects that were not apparent at the time of the drugs' approval, the US Food and Drug Administration said Friday. The new Propecia label will include "libido disorders,