Medicine

Every morning I take a Paroxetine medicine that prevents me from getting panic attacks and helps me function in my daily life. Today I had to get a refill on my dose and went to the pharmacy. The main distributor for this medicine is Glaxo Smith Klein and their version is called Seroxat (Paxil in the USA, there are actually different names for different countries, see the above link) and last time I checked it cost around 500 dkr which is pretty much. So I usually get a copy medicine that is a lot cheaper but usually costs around 150 to 200 dkr. But today I was pretty amazed, got a copy medicine from Ratiopharm which I think is stationed in Ulm Germany and it only costed 70 dkr! Now that is just amazing I think. How on earth can someone sell medicine for 500 dkr when a similar product (which perhaps has some other side effects, but how many patients suffer from those?) costs 70 dkr? What is the economics of this? I don't understand this.
I would think that when someone sells a cheaper product then you and can offer all the supply then that seller would force you to sell your product cheaper. But this does not seem to be the case in the pharmaceutical industry.