I should first say that I am not a medical professional.
I apologise if I'm coming across as a bit anal, but I would also like to clarify with you the reason for needing to take an anti-emetic regimen. Is it to help with a preexisting condition, or Is it for the purpose of preventing vomiting as a result of subsequently taking a lethal dose of drugs to end your life? If it is the latter, could you specify which method: Nembutal, SN, Amitriptyline cocktail, DDMP cocktail...
I have checked the interactions between olanzapine and meto and came across
this article on WebMD. I believe this source to be reliable. There is a medical warning at the very start of the article:
As such, I could not recommend taking meto with olanzapine.
Having investigated a bit further, I found the following article that states that olanzapine itself has anti-emetic properties:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4093458/
I'm not sure how much further advice I can provide. Maybe others on this forum with better medical knowledge can assist.