I have used RR with Bogey with some success. But I have found that the ThunderShirt is like a miracle for all types of anxiety from car ride to thunder and fireworks. Have you ever seen them? There is an entire thread about how well they work and I think you can now buy them from Petsmart. But I have to add that neither alone did the trick. I've been most pleased when I have used the TS and RR together. It's amazing the change and how well he does.
As for you original question about side effects. I have seen none with Bogey and have never heard of anyone else mention any. Good luck and take a look at the link
http://www.yorkietalk.com/forums/yor...p-anxiety.html