pethidine ("demerol") when injected can be very euphoric. When i was new to opiates i had lots and lots of IM pethidine injections, and i LOVE the stuff. I have never tried it IV...i can only imagine it would be even better than IM; yeah....i REALLY REALLY like pethidine & think its very underrated. Whilst IM shots lacked the beautiful, breath-taking rush of IV diamorphine ("ooohhhh!"), it always was a good painkiller & left me feeling like i was floating in a warm cloud....i would almost get those feelings where you think your somewhere else...not really like tripping, more delusional, but very enjoyable IMO.