Well, for analgesia, 10mg of IV morphine is equivalent to .3mg of IV buprenorphine (and since sublingual buprenorphine has a 30% absorption, you could say around 1mg = .3mg IV). I plugged the equivalent IV dosage of morphine to 30mg of oral oxycodone into
this narcotic converter, and found that 15mg of IV morphine is approximately equal to 30mg of oral oxycodone.
This would mean that a rough estimate for an equivalent dose of buprenorphine would be .45mg IV, or around 1.5mg sublingual.
The real problem with converting dosages of full agonists to buprenorphine is that bupe has a cieling effect, meaning that at a certain dosage, the agonist effects plateau. It would be great to know
exactly when an additional milligram or microgram would not produce further opioid activity (with acute dosing), but we really don't, and it seems to vary from person to person. However, from what I've read (as this topic has always interested me), the ceiling is likely around 4mg when taken sublingually, and 1.3mg parentally.
A lot of people from what I've read on this site seems to experience buprenorphine as being very different from other opioids, even when taken with little to no tolerance at all. I have to disagree based on my own experiences with it. Whenever I've kicked on my own and havnt used any opiates in 3 days or more, suboxone will get me really smashed, even if I take just two mg, and it really feels exactly like any other opiate, perhaps a bit more stimulating at times, but I wouldn't say anymoreso than oxy (also a Thebaine derivative). When I detox off of methadone completely, and have a couple weeks clean without using any opioids, I would love to get another script for suboxone, and just take it every once in a while to get buzzed instead of going out and copping.