Hi, ive been looking all over the internet for the answer to this question:. After taking suboxone strips(under the tongue,not iv) how long does a person have to wait until they will be able to feel the heroin( iv only) . Naloxone only blocks effects of opioids if injected right? So lets say i ate my last piece of sub 4ish hours ago, will i feel this heroin shot ? Or how long should one wait? I DO NOT want to waste it. Thank you!!!!