Dave and Victoria, Cinnarazine was the first med I ever tried when my MAV ramped up something awful after a bout of labrynthitis some years ago. And it is the only med I’ve been able to take without terrible side effects, which is something of a miracle for me, being super med sensitive. It didn’t do much for the dizziness really but helped with the nausea. After I stopped taking it regularly ( because it wasn’t making that much difference) I used to carry it around with me in my bag for sudden flareups or for when I got caught out with the dizziness. It could have been a placebo effect I guess but for a few years it gave me a certain peace of mind and did seem to take the edge off slightly.
Vic, I also get true vertigo as well as being dizzy to a greater or lesser degree 24/7. My acute vertigo attacks, when I can’t even stand up let alone move without the room spinning, come and go apparently at random. Although I’m at long last beginning to see a pattern - I think - super tiredness, combined with super stress (of a particular kind too detailed to go into here!), plus too many divergences from the diet. That said, I’ve also had them strike in the past right out of the blue (although I suppose there may have been triggers then but that was way before I was looking for them!) Attacks of that nature occur perhaps once a year, sometimes twice.
I’ve tried many remedies and meds to try to abort them, as I’m completely out of things for at least 24 hours, and had an awful one that kept me bedbound for 3 weeks. For me personally, I’ve come to the conclusion that only time will set me right. So I just sit it out, or rather ‘lie’ it out in bed. No med has ever worked to cut the process short, so I’ve stopped taking anything.
Out of all the meds I’ve tried though over many years, cinnarazine would be the only one wouldn’t be too scared to try again.
Interesting you say about getting diarrhea, I always need to empty my bladder ten times as much as usual, so annoying when you can’t move!! In between these acute attacks, I very much deal with all the symptoms that others on this board go through but after each episode it takes me at least a week, maybe two, or occasionlly even longer to get back to baseline. And of course the whole experience is truly depressing and demoralising.
Mind you, believe it or not, despite what I’ve written, things are vastly improved from how they used to be!! 
Brenda