My 8 month-old Beagle is still suffering from Car Sickness

My 8 month-old female beagle Tweetums still easily gets carsick even when just 15 minutes from the start of our ride. I thought car sickness was only in puppies. But my Tweetums has not outgrown being carsick and now we have to bring her along to spend a long weekend at the lake.

How can I possibly keep her from throwing up? Is there an OTC medication just like those for children? I don't want to starve her all the way to the lake.

Any advice will be highly appreciated.

Thanks!