The GAO noted the difficulty in criminally prosecuting the illegal sites. "Piecing together rogue Internet pharmacy operations can be difficult because they may be composed of thousands of related websites, and operators take steps to disguise their identities."
Baney concedes that one concern is that the illegitimate sites siphon off profits from responsible pharmacies, but a greater concern is that they are health threats.
An extreme example is the death of Marcia Bergerson, a Canadian resident and U.S. citizen who died in Vancouver Island in 2006. The coroner concluded that her death was caused by a lethal prescription that was contaminated with levels of lead, titanium and arsenic, according to the Alliance for Safe Online Pharmacies, which keeps track of cases of this nature.
But often the danger is not as obvious, Baney claims. She suggests that many deaths are caused by drugs purchased from phony pharmacists, but go undetected because the deaths are blamed on underlying health problems, such as cancer or high cholesterol.
"Often people will say, 'the cholesterol got the best of him,' but they're not asking, 'is the medicine legitimate?' It's really hard to know the difference," she said.
Catizone said he and his colleagues at the National Association of Boards of Pharmacy frequently make purchases from rogue sites to establish that they are illegally selling drugs, but shutting them down isn't easy.
"To shut them down, we alert the FDA, who alerts the authorities in their country," he said. "If you look at the limited resources, this doesn't work well."
Catizone and other groups are trying to educate consumers on how to purchase from safe online pharmacies.
The NABP was recently awarded the internet "pharmacy" domain, he said, and wants to move all legitimate online pharmacies to the domain in which all approved online drug outlets would end with a ".pharmacy," Catizone said.