Overdosing on just about any drug can poison you. Our own TKI's are very toxic. Overdosing on them can poison you as well. Taking non-pharmaceutical grade drugs like fish tank cleaner* is also not recommended. If people go out and dose themselves without any medical knowledge or oversight, then they don't want to be here, alive, on this planet.
Chloroquine's effectiveness is anecdotal:
https://nypost.com/2020/03/22/florida-man-with-coronavirus-says-drug-tou...
But then people do stupid things:
*https://kfor.com/news/arizona-man-dies-after-taking-medicine-touted-by-t...
For the vast majority of us - even if you acquire Covid-19, it will run its course most with few symptoms and some with a flu like response. For a few who have weakened immune systems and other underlying chronic conditions (not CML in remission) and are elderly (over 70), there is a greater risk Covid-19 can progress to pneumonia and be life threatening. For those people, Chloroquine 'may' hold promise. We'll learn soon if taking it by a larger number of patients if it truly works. My friend in Houston was given Chlorquine and it dramatically improved his condition (his Covid-19 progressed into pneumonia) and he is now home. So there is cause for optimism.
(Note: The only proven way to know for sure if a human treatment is statistically effective is a double blind clinical trial. These take a long time - months to years to conduct properly. They are very expensive, but are the only approved method to learn cause - effect, results and safety. In the case of Covid-19 and other maladies where time is of the essence, a clinical trial may not be practical in the short term. This is where anecdotal evidence can be useful. It is why we take vitamin D, curcumin, vitamin C and do other things (i.e. fasting) because there is evidence they can be effective in some cases and are safe when applied to CML. Are they proven? No. But they are not unproven either.)