Metabolism usually slows while on opiates, whether it be methadone, heroin, buprenorphine, or oxy. And this has an effect on the amount of stomach acid produced, and the amount of time food spends in the stomach... Usually food passes through the stomach quite fast, and it is in the intestines that a lot of the nourishment gets absorbed... Anyways, I used to have this problem while on heroin, and it would only be an issue if I didn't maintain a healthy diet. For example, on days where I'd eat late breakfast, and a small dinner, I'd often wake up with a nauseous feeling and in many cases, a glass of water or a cigarette would send me straight to the bathroom, puking. And this usually occurred as a result of A) very high doses of heroin, or B) if I was malnourished. Anyways, try keeping a regular schedule, in terms of your diet, and make sure you eat enough. Having lowered metabolism, and a stomach full of nothing but acid and fluid, will result in those nasty nauseous mornings. Of course, people are different, and some people have stomach issues that persist even when not using opiates, such as ulcers and the likes (Kurt Cobain used heroin as a way to kill his ulcer pains, and eventually it ended up as a vicious cycle, where he'd battle his ulcers with heroin, which in return made the ulcers worse). So eat well, and exercise, keep your metabolic rates as high as possible while on opiates, and see if that helps... It can take weeks to adjust, if you have been on opiates for a long time. Funny, I just got back from the clinic and posted in the
Bupe megathread about eating habits, opiates and wd's and so on... I can't help myself, but to round off with the same pun as I did in the megathread post... Food for thought
EDIT: I just spent the past two days in a semi-wd'ing state, and I used methadone to get through until todays collection of buprenorphine, and I did notice that the methadone had quite a profound effect on the stomach, compared to other oral opiates I've tried... Of course, the body is adjusting to me switching from bupe to methadone, but it really affected my appetite, and I haven't really eaten much since the first dose of methadone, and I felt a little queezy the two days on methadone, especially in the mornings. And as smackcraft mentioned, it also took me at least an hour to get over it, get something in my stomach (yoghurt and muesli), and get on with the day... Pain in the ass when one has to be somewhere at a given time (i.e. work or school).