A few things came to my mind. I've never had vertigo and don't get headaches. I've been taking grape seed extract for 20+ yrs so I trust this antioxidant helps So Much. I've posted about it a lot here.

A friend who has dealt with neuropathy for 15 some yrs and took gabapentin, talked about the vertigo when she was taking that med. She's off the med and has been taking the grape seed ex and I never hear her talk about vertigo. she looks 100% better too. She says she is feeling better.

Another friend has dealt with vertigo and has low blood pressure and takes some other meds so there is probably a connection there with the vertigo. She has tried grape seed ex and pycnogenol and says due to the colitis issues she just can't take it.

http://umm.edu/health/medical/altmed/herb/grape-seed

Well, that's my 2cents. Hope this helps some.