Websites for Pfizer's smoking cessation drug Chantix, erectile dysfunction drugs Cialis, marketed by Eli Lilly, and Pfizer's Viagra were the top three online branded pharma product portals driving offline consumer prescription requests, a new study shows.

The product site rankings were based on an online consumer research study of 5,112 US adults conducted by market research firm Manahattan Research.

“Having the most unique visitors is no longer the ultimate goal of a successful pharmaceutical product site,” said Manhattan Research president Mark Bard in a statement. “Brand teams and agencies are being challenged to demonstrate the economic and strategic value created by these online destinations—beyond the raw number of visitors or page views.”

The study also found that the top activities consumers currently conduct on product sites are researching side effect information and reading educational information about the condition treated by the product, said Meredith Abreu Ressi, Manhattan Research VP, research. “Two areas of unmet demand or future interest include the ability to compare differing features of products within a therapeutic category as well as cost information or discounts/coupons,” she added.