This is the first time anyone else has described what happens to me! I described it to my doctor as like someone shoves me backward and pulls the floor/ground right out from under me. I try to grab something if available but usually down I go and instant dizziness and nausea. I wasn't sure if this was vertigo. I don't get the "spins with vomiting" like is described on this site. I often find myself on the ground not knowing how I got there and not seeing anything I could have tripped on. I have found myself in a heap at the bottom of the stairs twice, not sure how I got there. Why is it when I describe these things to my ENT and Neuro they act like they've never heard it before?
Meniere's can cause a drop attack. But similar can happen due to other things going on in your body. My mom had an issue when she would first stand up her blood pressure would plummet so about 3 steps in to the "walk" she would be on the ground with no idea of how/why she got there. Low potassium can also cause a similar issue. There are a lot of potential causes. As your vertigo lasts less than 5 minutes, I am not sure that it would be Meniere's. Could be benign positional vertigo. When I had a period of about 6 weeks where I was "dizzy" (not vertigo) and I could see the room shift back/forth only, I remembered and took a Meclizine. It helped almost immediately to stabilize the vision.