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You can also try conditioning the dog to riding in the car. Start by sitting in the car with the dog with the car not running. Give lots of praise when he doesn't vomit. Then travel a small distance the next time. Give lots of praise when he doesn't vomit. Then you can progress to longer rides.
If you start to see drooling, this is a signal that the vomit is coming so you should stop the car and let him get out and walk a minute.
Dramamine is effective as well, as is benadryl but you want to avoid medications if you can. 90% of car sickness is not about motion, it's about stress. The least stressful you can make the ride, the less he will vomit.
With some work, you can make this a good ride for everyone.
Let me know if you still have questions.
My vet recommends benadryl at the dosage of 1 mg per lb of body weight.
I am not sure about dramamine.
I hope this helps more!