Tianeptine has an extremely short duration of action, I got really really heavy into using the sodium version a few years ago. Started at ~100mg, but at the end I was using ~5-7 grams each day..........and not feeling hedonistic-ally high and wonderful all day, but just staying out of W/D. Doses only really lasted 4 hours max. The "high" was really just about 1-1.5 hours long (while I actually could get high), and after was just a feeling of normal before the tianeptine completely left (and that window of normal got smaller and smaller each day).
I was waking up every 2-3 hours through the night in W/D, and let me tell you, eating that much tianeptine fuckin sucked. It'd blast through my stomach and I'd throw up pretty often, most usually on the morning. The taste of that was so bad, the stomach acid and tianeptine mixed to make this acidic slush thatd get in my nose and everywhere and the taste would never completely go away, even with brushing my teeth 5 times in a row and gargling mouth wash. I had 2 shipments arriving each week, the max i could order without a research grant/permit thing. i had to spring for overnight shipping, and eventually, I spent so much each time I'd get free overnight shipping (that should tell you how much I was spending).
If you've been addicted to hydromorphone or any other opioid, the last thing you want to do is replace that with a MUCH shorter acting opioid that operates like tianeptine. I'd pretty much guarentee your doses would fly out of control, and since youre actually prescribed them, it'd be pretty bad to be OUT of your monthly script after 3 days.
It'll take care of that opioid absence problem. but not for long, and it is the least sustainable opioid to use for anything except what its prescribed for in the suggested doses and NO more