I have been doing the opiate thing for about 7 years now and after some time you really put a lot of effort into finding things to help with withdrawal, although it always ends up just being a bridge to help me along until I can do opiates again I have found some things that work. Some of these things could probably help somebody quit if they really wanted to / needed to. I won't cover all of them, just the ones that pertain to this thread. I'll address Gabapentin (neurontin) and Pregabalin (Lyrica). I have used both and find these two drugs to be the most effective drugs to treat withdrawal. I'm not counting things like suboxone, tramadol, or codeine because that is retarded because they are all opiates (or partial opiates) so you might as well just be doing oxys or hydros and saying that they are helping your withdrawal. Well no shit, thats because they are opiates.
Okay so to get to my point. Lets talk about Gabapentin first. This drug has limited effectiveness when it comes to treating opiate withdrawal. They come in 100, 300, and 400 mg capsules and 600 and 800 mg extended release tablets. In order for Gabapentin to help with withdrawal you need to take high doses. (at least 900 mg, but 1500-3000) for maximum effectiveness. I want to add that for me, for whatever reason the capsules dont work worth a crap. I can take 2-3 grams of capsules and it helps a little bit but Ill still have the runs, the sneezes, the hot flashes. It helps with the appetite a little and helps with the other symptoms I mentioned marginally. The 600 and 800 mg tablets seem to work better for whatever reason. Over all though lets say you are in full blown opiate withdrawal from a decent habit lets go with 80-100mg of oxy a day. You are at a 10 on a scale of 1-10 on the opiate withdrawal scale. The Gabapentin will take you from a 10 to like a 5 on the first day you use them, but tolerance builds fast after a few days gabapentin barely works and might bring you from like a 10 to an 8.
Now lets talk about Lyrica. I fucking love lyrica! it comes in 25, 50, 75, 100, 150, 225 and 300 mg capsule. Lyrica works great for withdrawal. The first 3 days of withdrawal always are the worst IMO and the first is always pretty bad and when the anxiety is the worst because you know all hell is about to break loose. Lyrica has taken me from a 10 on the opiate withdrawal scale to like a -5. I will go from feeling like dog crap to feeling high as a kite. Unfortunately this is only the case for one day for me. I will usually take about 500 mg of lyrica in order to achieve this effect. However, if I take 500 mg for the second day in a row it kind of just makes me sleepy and works on about the same level as gabapentin (well a little better) but youll wanna double your dose each day to get continuous help from the lyrica.
After about 3 or 4 days help from either of the drugs in minimal, but you should be through the worst of your withdrawal anyways (or have found some smack

), if you dont have a huge benzo tolerance you could pick up some xanax, klonopin or valium to help out as they are similar and work on the same (GABA) receptors as the lyrica and gabapentin. With my gigantic benzo tolerance (10mg of xanax doesnt even effect me ) I find benzos to be not helpful at all besides to help sleep during detox.
As others have mentioned it takes about 2 hours for Lyrica to start working (same goes for gabapentin) and lyrica can really fuck you up. I got fired for going to work on lyrica once because I was falling into things and slurring my speech (oopsy daisy). Doses of higher than 800 mg can be excessive and will probably just lead to you passing out for 16+ hours.
Lyrica is the best drug for opiate withdrawal. I am coming to the end of a pretty good H binge right now. Just got up and did a vicodin. I have 20 of the 100 mg lyricas right now so I'm going to take 4 or 5 of them and enjoy my day.