When the Web site debuted in February, Canadian pharmacies filled 765 prescriptions during the first month.
By August, that number was cut in half to only 364 prescriptions.
A local pharmacist says safety concerns and lack of support from the Food and Drug Administration might be reasons for the decline.
"What's the perception of safety from the public? Maybe the public is getting concerned that what they're buying is not what they expect," says John VanDeVoort, Sacred Heart Hospital's pharmacy director.
The governor's office says he isn't disappointed by declining sales, saying the website provides a last resort for residents without insurance, Badgercare or Senior Care.
The website can be found at: drugsavings.wi.gov