Nausea in my experience is a very common side effect for many people who try heroin for the first time too (generally this is a common side effect of opioids given as painkillers as well). However, I myself have never experienced nausea from any opioid until the first day of buprenorphine maintenance when I suppose I was given too much, after 9 years of addiction. The first opioid I took was codeine, I took 100mg of codeine phosphate in 10 pills with some herbal extracts, washed it down with some beer and boy, was it a very nice, chilled out ride lasting for like 6 hours, I had never felt such a pronounced surge of inner peace, all worries and anxiety gone in a matter of 20-30 minutes and instead of that shitty feelings glorious serenity. I chatted to a guy I knew from a forum for a couple of hours, didn't like the guy at first, but with codeine I was free of prejudice caused by fear and anxiety. I managed to keep squeezing this joy of the codeine fruit for 1 year or so, then morphine and heroin followed. The first time I took heroin, I shot it up on the train back home, it was 1/3 of a 0.25g, again I felt the surge of inner peace but I was taken up in the heroin cocoon almost instantly, much deeper than first few times of codeine to the point of being slightly psychedelic when I found myself on the edge of nodding, felt barely any itching unlike with morphine but other than that what follows minutes after the injection is very similar for both opioids. The world around me felt so "organic" and at the same time I was so distant from it feeling my body thoroughly anaesthetized and with my head up in the clouds swept by warm wind. The relief you feel when you take an opioid for the first time after suffering for months from depression, anxiety, and all the shit that eats you from the inside is indescribable, granted you perceive the high differently then, on top of that personal reaction to a drug can be very different. Many people I knew who started taking opioids didn't feel much during the first few times no matter whether it was codeine or heroin, with codeine often at the beginning all you feel is just itching and slight sedation, heroin is an opioid of a different calibre, so the side effects are stronger. One girl who used heroin for the first time in my presence continuously reported feeling very little although she was nodding out hard and puked like a cat, hard to believe it could feel so subtle being so strong at the same time.
That is not to glorify heroin or other opioids though, the anxiety stronger than that you felt in the beginning, pain in all of your body with your mind and heart cracking while moving around restlessly bedridden smelling your vegetating shit for a week or more, all that start presenting a different image of opioids to you when you feel withdrawal for the nth time. An even deeper understanding of heroin doings comes when you realize how disabled you are mentally, physically, and socially after years on an elusive journey for eternal peace.
