I've said this before and I'll say it again. Please please read up and prepare before taking amitriptyline overdose.
You need antiemetics, and start taking them a couple of days before you do it.
All the advice I've found recommends something like diazepam AND lorazepam. Diazepam is slower acting but lasts longer, while lorazepam is fast acting but shorter duration.
Tablets can be crushed and put into capsules, or dissolved, or mixed with a little jam or honey etc.
Wash down with your favourite alcohol. Recommended.
My daughter took around 8g of amitriptyline, and some mirtazipine. She did it on impulse. She didn't take any antiemetics. Only some beer. She threw up all over her room. But died in less than 12 hours.
Her death was anything but peaceful. It really cuts me up knowing she died like that.
More amitriptyline would have hastened it.
It is a well recommended method, if you do it right.
I have a pile of amitriptyline (on prescription) but the diazepam and lorazepam are difficult to get here. But I know of a reliable source (illegal)
I can get prescription antiemetics for virtigo.... I get it bad from time to time. The whole place spins round, literally. It's really weird. Need help to walk to the loo and getting on it, can't keep my balance. Everything just spins round. Can last a day or two. Can't sleep cos still spinning when you shut your eyes. Antiemetics sort it out. One to try on your doctor's? Read into it first though, get your facts right before trying it.