Would you be surprised if the answer is AstraZeneca’s Nexium? The web site for the heartburn med, known as purplepill.com, generated the most site traffic in this year’s second quarter, with more than 1 million unique visitors, a 55 percent increase from a year earlier. Runners-up include sites for Takeda’s Actos diabetes drug and the Sanofi-Aventis Ambien CR sleeping pill.

“AstraZeneca has aggressively marketed Nexium this year, running approximately twice as much online display advertising in Q2 as either of its major competitors, Prevacid and Aciphex,” John Mangano, senior director of comScore, says in a statement. “This additional marketing muscle appears to have helped generate strong site visitation.”