You want an antiemetic that is a dopamine antagonist (D2), so antiemetics such as ondansetron will not work as they have a different "target", but antiemetics such as metoclopramide and domperidone will. Using an antiemetic isn't
as crucial when compared to SN, for example, but it is still recommended.
How does one get anti-emetics, and is it absolutely necessary?
I saw a user on here documenting how they managed to get their hands on metoclopramide from a pharmacy without actually having any symptoms. I don't remember who user this was, but I did write a summary of what he/she said.
"Metoclopramide is an antiemetic often used together with drugs/medication so as to not
throw them up. It is also used as a treatment for migraines. In many countries,
metoclopramide requires a prescription. The easiest way to obtain it is to consult an online
pharmacy and provide them with the following information about your migraine:
● You have moderate pain that's either left or right-sided (not localised).
● You have been vomiting.
● You do not have a history of migraines and have not been treated for it before.
● You are not taking antidepressants (SSRIs, SNRIs or TCAs).
● You've tried over-the-counter medication such as ibuprofen, but not for an extended amount of
time.
● You do not know why you are having migraines.
● Ask for something that would stop the vomiting. It's interfering with your
work/day-to-day life.
Make sure you have a believable story before you consult the pharmacy."
The person claimed it worked well for them, but I haven't tried it myself.