I am frequently asked about taking prochlorperazine (Buccastem® or Stemetil ®) to treat nausea due to labarynthitis, vertigo or dizziness. It is a drug I would be happy to prescribe and have used it myself as have my two breastfeeding daughters. It seems a frequently asked question when the air pressure changes rapidly. Prochlorperaszine may also be used for nausea

prochlorperazine and breastfeeding factsheet

see also https://breastfeeding-and-medication.co.uk/fact-sheet/betahistine-and-breastfeeding