won't ever tell you that their drugs are worse than the hurt! Gotta admit though, there are times when I really appreciate them. Especially when I can't sleep at night for the pain or the coughing.
I get where you are coming from and I understand that it is sometimes as bad to take drugs for some conditions as it is to endure the conditions. I guess one has to make that decision for themselves. Good theme, title and content.
~ Gee.

Interesting topic - has a lot of promise I think, but maybe a tweak here and there could bring out the protagonists - and the message more clearly.

I'm not sure who is the baddie here; perhaps you are seeing the medical person here as a 'quack' (cum 'drug pusher' arguably for good reason as they wait too long to treat something) but maybe you are taking on the term the way medicos label complementary medical practitioners? I'm not quite sure. Correct me if I didn't get it right.

Here is your poem with some suggestions:

if all side effects they tell
how will they their drugs sell (cumbersome: consider: leave out 'they' and it flows better)
then no one will buy them (consider: leave out 'then' as frees up the line)
none living in hell... ..

do you know a quack (put 'a quack' on the next line with 'once said')
once said
I can't treat your breathing problem ..
but catch pneumonia .
and (put at start of next line)
I will treat you so very well.. (leave a spare line break here)
your breathing problem
none will then know or tell (could we leaves out 'then' or consider: 'will have been squashed'
even you will feel better
and swell.. ('swell' seems outdated and not used much nowadays - perhaps not needed)

so says the drug dealer
so it seems
Albeit silently.... (interesting closing lines love first line, then confused as to 'so it seems')