The problem is that with high potency, you also get more side effects for the same "painkiller" effect (also depending on absorption velocity). Therefore, using

The problem is that with high potency, you also get more side effects for the same "painkiller" effect (also depending on absorption velocity). Therefore, using something such as remifentanyl in the mix would almost certainly be counterproductive if you are looking for the "high". It would displace fentanyl, and be more risky. And first of all, it is far more expensive than fentanyl.