There is fundamentally no difference between Generic and Brand Advair Diskus, whether purchased from a Canadian online pharmacy or elsewhere. The only difference between brand and generic drugs is that the generic drug is not manufatured by the Brand manufacturer, although the strength and composition of the drug is exactly the same. Generic Advair Diskus will be as effective as the Brand Advair Diskus.

Online pharmacies from Canada also sell generic Advair Diskus, but make sure that they are selling FDA approved generic. Most of the legit pharmacies like TruMedCanada.com sell generic advair diskus which contains Salmeterol/Fluticasone

in various compositions as 100/50 mcg , 250/50mcg and 500/50mcg. I started buying from them only when they confirmed that they supply genuine generic advair manufactured by FDA approved plants overseas.

Here is their link :

http://www.trumedcanada.com/rx/advair.diskus.aspx

Good luck!