Okay, I have no idea what SN or ppeh is or any of the other abbreviations, newbie here, so really I probably should not put my two cents in, but....
Redheads. Natural redheads have a higher need for anesthesia, I used to dye my hair dark brown, from the time I 14, at 17 when my appendix got infected I woke up on the operating table and stuggled until the pulled the intebation tube out as I forced my way into a sitting position to throw up. I saw my stomach opened already as the appendix burst, they threw a sheet over the incision and handed me a curved plastic bowl to puke into. The doctor asked me why I was awake and I said I don't know. He asked if I felt better since I puked. I said yes, he asked if I was a natural redhead, I said yes. He then turned to all the assistants and asked had anyone checked the carpet and none had. Raising the bottom of the sheet he pointed to the fiery red patch between my legs. Told me lie down, ordered the anesthesiologist to to put me back under. I felt them reintibate me and I heard the doctor chewing them out, I finally got my hand to touch him. I asked if I could hear anything, I flapped my hand, he asked if I could feel anything, I flopped my hand. He shot the anethesiologist a gruff look and things finally went black.
Point of the story...Genetics also plays a role in how much it takes. I took two large bottles of benedryl, crushed and mixed with root beer so I would not vomit, locked myself in the house with no phone and went to bed. Woke up the next day. I had apparently tripped balls and danced with fairies and fed them butter, it was all over the apartment. And here I still am. That was my last attempt almost 20 years ago because I am terrified nothing is going to be able to kill me, only make me really sick and more miserable and despondent than I already am.