(April 8, 2016, 12:22 PM EDT) -- WASHINGTON, D.C. — Twenty-nine federal lawsuits alleging that Viagra increased the risk of melanoma were centralized April 7 in the U.S. District Court for the Northern District of California (In Re: Viagra [Sildenafil Citrate] Products Liability Litigation, MDL Docket No. 2691, JPMDL)....