My wife replaced Losec (called Prilosec in the US) with a generic version and felt that the latter worked somewhat better. It is still prescription in Canada, BTW. The original was a slow release tablet and the generic a slow release capsule, so perhaps not entirely comparable.
On the other hand we have a friend who simply refuses to take any generic and has to pay the difference in price. She is simply convinced they cannot work as well and even uses my wife’s experience to justify that they are different. This being Canada there cannot be that large a difference.
For a while I was prescribed Ritalin on a as needed basis. He wrote a script for the brand name and instructed me to try this out first to see how it is, insurance didn’t like it be he persisted and they paid. Then switched me to generic to see if the effects were the same - they weren’t. One was a calm feeling of normality that allowed me to do things the other was a anxious feeling that I had to do things. First was pleasant the second was not. I did try another generic of it (another brand) and it was a little better, but the original brand name was much much better, like no side effects and all benefit.
I do wonder if the generic brands manufactures sometimes intentionally mess it up as not to step on the cash cow of the original manufacturer, for a nod-nod wink-wink reciprocal agreement. There certainly seems like there is an incentive to do so.
I think you are saying that the inert ingredients are not inert but part of the delivery system. That seems important to consider.
When the first one went to generic, it worked fine for a long time, and then my pharmacist switched to a different generic, and it didn’t work at all. I ended up going to a different pharmacy to get the generic that worked for me. Fortunately, that medicine eventually went OTC, and now I can just buy the brand name again.
When the second one went generic, it again worked fine until the pharmacist switched to a different generic, which again didn’t work at all. That time the pharmacy was able to get me the original generic, which I am still taking.
These changes were not a reverse placebo affect, since I didn’t even pay attention to which particular company was supplying the generics. They just suddenly stopped working, and then I figured out why.
When my third medication went generic, I was very nervous that I’d have another problem. But so far, it’s been fine.