show me a study where the mouse model had negative correlation to the human trial : https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2746847/ , with relation to diabetic drugs and anti malarials?

Chloroquine COVID19 trial has been discontinued in Sweden due to severe side effect, most notably seizure and vision problems in patients.

Original article: https://www.expressen.se/nyheter/carl-40-fick-kramp-och-syn-...

I expect this will appear in international media soon, if it's true. Note that I don't speak Swedish and I used an online translating tool to read the article.

Well, keeping track of metformin use would be pretty easy. You could even exclude those using it from trials, unless they signed off after full disclosure.