OTC antiemetics are pretty weak and ineffective these days, which is why they're not recommended. They won't keep you from vomiting with SN.
Domperidone is often use an alternative to meto. I'm not sure if there's any OTC version of it in the US though.
It's banned in the US. There is a concern about lactating women using it to generate more breast milk, so naturally we can't have any anywhere in the country. (You just can't make this shit up. What a fucking world we live in.)
hxxps://www.fda.gov/drugs/investigational-new-drug-ind-application/how-request-domperidone-expanded-access-use
Domperidone is not currently a legally marketed human drug and it is not approved for sale in the U.S. On June 7, 2004, FDA issued a public warning that distributing any domperidone-containing products is illegal. FDA also issued an Import Alert instructing FDA field personnel to detain shipments of finished drug products and bulk ingredients containing domperidone, and refuse admission into the US. FDA took this action because of the concern about the potential serious health risks associated with the use of domperidone by lactating women to enhance breast milk production.