Ah, well domperidone is an anti sickness tablet but it's not an anti histamine. It's a motility drug (prokinetic), my doctor prescribed it for nausea and I find it helps with my GERD too. But if you're looking for an anti histamine, have you looked at the sea sickness section of your local pharmacy? You can buy OTC several anti histamines in that section for the purpose of preventing nausea. You can buy "Avomine" which is promethazine theoclate or " Phenergan" which is promethazine hydrochloride. However I noticed that Phenergan says it's for short term use only and can have a sedative effect, so I don't think that would be suitable for your situation. Might be worth asking a pharmacist about Avomine though? I was prescribed it for for morning sickness in the past.