I would be careful with dimenhydrainate as it is found to be related to dementia likely due to the fact that it's anticholinergic. It's basically the opposite of a nootropic.
I was aware of this already—thanks for bringing it up though, since I think it’s important that people be aware of it. Unfortunately I haven’t found an equally effective yet safer replacement for nausea & allergies. Ginger works pretty well, but iirc that’s because it’s also a mild anticholinergic/antihistamine.