what people who are addicts call "euphoria" is in fact a feeling of well-being, of feeling healthy, of BEING healthy. opiate-dependent people need opiates to be healthy. a junkie who shoots heroin doesn't want to feel "euphoria" - that's what other people tell him he's gonna feel - but it's just the feeling of being healthy. nothing more, nothing less.
healthy people don't like opiates. today, nearly everyone will find opiates to produce nice effects, because nearly everyone isn't healthy. that desease, called "addiction" spreads all over the world because of the constitution of our society. it's the modern way of living, the wars, the suffering, the traumata, that causes a wish - the wish for feeling healthy, feeling good. addiction is a desease that can be treated with drugs. but you have to take the right drugs. opiates are the only ones that aren't harmful to the body and mind and which are perfect for treating the symptoms (all psycho-deseases like depression, borderline, burnout and so on, the feeling that you lack something "good", the lack of satisfaction)...
sorry, my english isn't the best. i hope you understand what i mean. i just wanted to clarify that euphoria isn't what we addicts feel. it's well-being. health.
fentanyl-derivates have a very strong sedation and respiratory depression, whereas the "high" (how you call it) is not as good as heroin's, oxycodone's/morphone's and so on. morphine also has a strong sedation and r.depr., codeine, dhc...
personally, the best opiates for an opioid-dependent person are: morphine-esters like heroin, nicomorphine and so on, oxycodone, oxymorphone, hydromorphone, morphine, piritramide, maybe ketobemidone...
addicts are given the wrong medication as a substitute: methadone is more of an analgesic than an appropiate medication for an addict. heroin would be much much better. substitution is bullshit anyways. people should get the treatment they deserve. opioids.
personally, i'd like to have heroin/oxycodone to be my basic medication. for the rush, i'd alter between hydromorphone, oxymorphone and piritramide/fentanyl. for basic medication, you need an opioid with a longer half-life, whereas for the rush, you need something that wears off quickly. hydromorphone is perfect. remifentanil would also be great, but it's not available and the high isn't that good, but the rush must be overwhelming. it's extremely lipid-soluable.