Without going into details, a year or so ago I was getting my hands on a lot of 5ml/5mg midazolam vials....holy fuking shit...
IV midazolam is like nothing else, it is the absolute epitome of 'stupifying'....I was opiate dependent at the time and I nearly overdosed over a dozen times in a couple of months...plus a couple of blue-faced overdoses that I wouln't have survived if I did not have a friend and naloxone on hand.
It's not so much the strength either...the oral bioavailability of midazolam is aound 30%, IV is 99%...so it is much stronger shot up...but the danger is in the EXTREME disinhibition and you're pretty much guarenteed to black out- and if you're anything like me there's a high likelihood of you blacking out and then compulsively redosing (generally making a terrible mess of your veins). I intended to shoot 12mg (the vials were all a 1ml/1mg over, so 2 vials) , I blacked out and ended up shooting 150mg (3 boxes/30 vials) and you know, dying for a little bit on my bathroom floor.
So I'm not just being one of those 'never mix methadone with benzos' kiddies, if you're on MMT you probably will know your limits well enough to be able to be safe...midazolam doesn't necessarily let you do that. It's used for anesthetic induction (to relax/render your unconscious and amnesiac so they can operate on you without you remembering anything- even if they fuck up and your wake up on the table, you won't remember it...seriously), so it's just so much more unpredictable when you're shooting it. It's not so much a specific risk, it's just shooting midazolam often leads to compulsive redosing and compulsively redosing extremely powerful sedatives in combination with methadone seems like a disaster waiting in the wings.
Really, I can't emphasise just how fucking powerful IV midazolam is. The rush is amazing, the effects are so fucking heavy, the amnesia is so fucking complete and you're left with no-zip-none-nada inhibitions. Even shooting an equivilant dose of diazepam with your 'done would, in my opinion, be safer than shooting midazolam. The line between the absolutely perfect god-nod and blacking out, shooting 30 vials over around 6 hours and having to suffer through the precipitated withdrawal from naloxone is just so fucking fine. When I took 30 vials and overdosed my girlfriend shot me up with naloxone and flumezil (the benzo antidote)...flumezil makes you feel like shit and can cause seizures. Overdosing...even if you're fine (all things considered), it still fucking sucks.
Please be safe...that 3 month period where I went through over 15 boxes of vials was so fucked...I'm so lucky that I'm not dead- cos that's all that it was, a little bit of forward planning (got diverted naloxone & flumezil too) and several imperial fuck tonnes of luck.