How old is your pup? Don't know what dosage of the dramamine would be advisable, sorry. Before you try to drugs though, you might want to try an herbal calming aid or ginger snaps--they calm the tummy
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When Stella was really little, she would get car sick on longer rides too, but once I stopped feeding her before we went for a car ride (at least within two or so hours of leaving) and she got her puppy car seat (helps keep her safe and out of my way while I'm driving...very useful!) she stopped getting sick and now she LOVES car rides because she can see out the window. I think sometimes they grow out of it too. Good luck!