I had a similar experience in Denver, which is detailed here. I, in fact, do have a reason to carry medicated toothpaste (sensitive gums). Specifically, the ingredients in many toothpastes can cause allergic reactions, and so I carry toothpaste that is only manufactured in 4.5 oz or heavier tubes.

TSA said I need a prescription to carry it on, which is, of course, impossible, because it is an OTC toothpaste which contains Fluoride, desensitizing agents, as well as does not contain other ingredients which I react to.

So, I am not sure what documentation to carry, and I am not cool with the idea that TSOs should have any access to my medical records, which is about the only documentation there is.