the way i can tell its safe for me to take suboxone after opiate use is when i feel the first symptoms of withdrawl (im talking about fast acting opiates, ex: heroin, morphine, oxy/hydro) when i feel the yawns and runny nose i dose suboxone, and 85% of the time i dont get Precip. WD's, a couple of times i felt sick, and dosed suboxone and went into Precp WD, which wasnt as bad as people say, it lasted 1hr at the most, with just a little more intensity of withdrawl feeling. i take suboxone mostly, i use opiates once in awhile, ill go like 5 days taking morphine, and when i feel sick i dose. sometimes im fine, sometimes i feel recip WD for an hour or so. now methadone, even if u feel any slight discomfort i DONT reccoment taking a suboxone, cuz of methadone's long half life..be safe and wait 72hrs after ur methadone dose..my girlfriend goes to the methadone clinic and she missed her dose one morning and said she was feeling sick and wanted a sub from me, i warned her not to thats its way too early regardless if she is feeling withdrawl, so i warned her, but her being stupid, feeling sick after going 24hrs without methadone, took a half of a suboxone, and wa sin intense Precip WD for 10 hours, it was pretty bad..her jeans were soaked in sweat, she was crying, nauseous, leg problems, and going to the bathroom. ill just say general rule of thumb, wait 24-36hrs after ur opiate dose to take suboxone, if u dont feel withdrawl, dont take the sub...generally 24-35hrs is how longu should abstain opiates before dosing suboxone