Two diabetes product sites – Merck’s Januvia and Takeda’s Actos – came in first and second, respectively, in a new study measuring physicians’ web habits.

The study, conducted by Manhattan Research, ranked drug product sites based on visitation rates from primary care physicians. Merck had the most product sites on the list, at three, which included Gardasil’s (#4) and Vytorin’s (#6) websites. Pfizer’s Chantix, a smoking cessation treatment, held the number three spot.

Actonel, an osteoporosis treatment marketed through a Proctor & Gamble and Sanofi-Aventis partnership, was ranked at number five. Seven through 10 are as follows:

7. Amitiza, a Sucampo Pharmaceuticals and Takeda product
8. Byetta, an Amylin and Lilly product
9. Avandia, a GlaxoSmithKline product
10. Aciphex, an Eisai and PriCara product

“This year’s rankings show that market events, rather than just advertising alone, can be critical drivers to brand websites,” said Meredith Abreu Ressi, vice president of research at Manhattan Research, in a statement. “Pharmaceutical companies need to ensure that brand websites contain the latest, most accurate content possible and can be found relatively easily by physicians using search engines to research pharmaceutical information.”