Not too toot my own horn, but I'm probably one of the most experienced people who can answer this particular question. I've years of experience with various preparations of oxy, taking them orally and rectally, plus have a strong understanding of the science behind it.
Firstly, just to reiterate, targin cannot be plugged.
Any pure "oxycodone" (including time release) or "oxycodone + paracetamol" or "oxycodone + morphine" (MoxDuo) can be plugged.
From the oxycodones perspective, the bio availability is similiar to taking it orally so no benefit there. However, if prepared properly plugging oxy gives you a MUCH greater rush and intenser euphoria, albeit the total duration of the experience is shorter.
However, on a personal note, I find that from a pain control perspective, plugging will control the pain just as long as oral admin. This make it in my view the best method for maximising rush, euphoria, and pain control.
To sucessfully plug, the tablets need to in a liquid. Below I've done a brief guide on how to plug the popular Australian preparations. All should use a 5ml syringe.
Endone/Oxynorm
Put the desired number of tablets into a syringe, and draw up water around 75 degrees celcius to half fill the syringe. Put a finger over the opening and shake until tablets are disolved completely. Draw up more water at 75c (the previous water will need to be reheated, as it will have cooled in the time you've been shaking/dissolving) and shake it some more (maybe 20 to 30 seconds). Leave it to cool for 5 minutes and then plunge. After plunging, and if you can be bothered, refill the syringe about a ml with luke warm water, shake, and plug it again as you may get a few more mgs that got stuck to the pluger etc. Can't hurt can it.
Oxycontin.
People often make mistakes when plugging this that lead to the decreased potency. The mistakes are water temperature and crushing.
I've bought a small evaporation dish from a science supplies store, which makes a great crushing bowl. For the oxy to be absorbed by the liquid, the pills need to be powdered as fine as possible. Pour the powder into the syringe (make sure the bottom hole of the syringe is cover or else some powder will come out). Best way not to lose powder is to cover the small end with your finger, pour the powder into the barrel, put the plunger top in gently (just enough to make a seal), turn the syring upside down and shake to get the powder to fall to the base of the pluger top then SLOWLY remove your finger from the hole. If you remove your finger to quickly, some powder may escape as the syringe chamber is slightly pressurised at this stage. Now SLOWLY push the plunger down towards the bottom, and sideways (so no powder falls out) draw up 2mls of 75 degrees celcius water. Shake for 2 minutes or so. Reheat the water to 75c and draw up another 2 mls and shake for 2 minutes or so. Now, ideally leave this for an hour. This way any oxycodone trapped in the time release mechanism will be drawn out into the water. At the very least, wait 10 minutes. If you've crushed you pill well enough, 10 minutes should get you 99% of the oxy I imagine. Now plunge it. To maximise your yield, you can draw up some more water, shake, and plunge that to get any oxy that clung to the plunger seal.
Why does the water have to be 75c?
Why does the water have to be 75c. Boiling water can make the syringes function poorly (losing liquid), makes the oxycontin powder turn a bit gummy and I've heard (but not confirmed) that it can cause some of the oxy to degrade due to heat. Too cool and the water will be less efficient at absorbing the oxy from the powder.
No Need to IV
Now, plugging using the preparation methods above is JUST AS GOOD as a feeling as IV'ing is, and so in my opinion there is no excuse for iv'ing oxy. IV'ing is dangerous too, and therefore an all-round bad idea. Plugged oxy has a similiar bio availibility to IV'd oxy as well, so no reason there.
Role in pain management
I have found the best pain management use of oxycodone is to take 1 oxycontin tablet or appropriate strength every 8 hourly if you have fast metabolism, or 1 every 12 hours if you have slow metabolism. For break through pain. Keep a syringe pready prepared with an appropriate amount of oxy in a box in the friedge (this protects it from light and makes it keep longer... atleast 3 days at full potency) on hand for break through pain. Plugging oxy is excellent for breakthrough pain as it hits hard and quickly.
Sorry for waffling
A lot of info there any good plugger already knows, and so sorry if I have come across as treating you like a noob. I figured if I'm typing this up, I may aswell make it suitable for beginners as well and so this post is designed for the world in general, not just yourself, but I hope you found this useful
