I'm likely going to take a few Amitriptyline the day I CTB - I'm prescribed them anyhow and I want to be as relaxed as possible.
When I had a stock pile of Amitriptyline, I did consider a massive overdose outside in the snow - I had found 4 places I could've CTB outside without being found for a while. But alas, I used the Amitriptyline recreationally. I'm fairly certain I further damaged my short term memory when I was taking large doses to knock out.
P.S. In lieu of Meto, Amitriptyline does have antiemetic properties.