So here we go. Where do you the draw the line between enabling and harm reduction? Does one assume that an OP such as this is going to do it anyway so you may as well give them clear instructions? The usual suspects are free to chime in here.
Only thing worth mentioning here right now though: an entire patch contains 4.2
mg assuming a Durogesic® DTrans® 25
µg/hour matrix/drug in adhesive type patch (note that this is manufacturer dependent i.e. some contain substantially more). This of course assuming you're able to perform a 100% extraction. And bear in mind that the LD50 of Fentanyl in humans is 2
mg (but which of course would depend on tolerance but that's a bit of a slippery slope in my opinion especially when poly-drug use is involved i.e. I've yet to come across somebody who is ONLY using Fentanyl).
Another worthy note of caution for anybody that happens to come across this: don't go listening to these heroes that apparently IV big doses of Fentanyl. What comes out of these patches is not of the Chinese variety or some shit off of the DN i.e. it's hard core and pure pharmaceutical Fentanyl. It is indeed "heavy artillery" as noted above in the previous post.
And I wasn't trying to be full of shit yesterday in my post above. It helps to spell the name of the drug correctly particularly in this instance and with this substance. The search function here is exacting i.e. it doesn't return "similar" results. Point being that anybody looking for a safe way to misuse or abuse these things isn't going to come across any harm reduction advice given on this thread if they don't make the same mistake in spelling when using the search function and searching thread titles only.
Here's probably one of the best harm reduction documents around on the topic. Unfortunately it's 15 pages long but I suggest that anybody going down this road reads every page and follows the instructions to the letter (this if you're not going to perform a total extraction and which is probably the more advisable route anyway given that your chances of getting all of the Fentanyl contained in the patch using the method detailed are slim):
Injecting Fentanyl - Minimizing The Risks