Looking at Stan's guide, he does name specific types of Anti-emetics:
- Dromperidone
- Metoclopramide
- Olanzapine
- Alizapramide
- Chlorpromazine
- Prochlorperazine
However, he also states that: 'You do not want any antiemetic though. Buying one for travel sickness for example works on the wrong part of the brain for the SN method. What you need is a dopamine blocker which have been listed above.'
Whilst he has not listed Phenothiazine (which is what Metopimazine is), specifically, from what I can see this is a dopamine blocker? So my assumption would be that it would be ok.
This is just my opinion though. I don't know if there is a specific reason he hasn't mentioned it, but if I have understood Stan's advice correctly, the most important thing is to get a dopamine blocker.