I have been reading about generics vs brand-name drugs. I've learned that generics go through extensive testing for bioequivalence (both rate of absorption and total absorption of the active ingredient). The statistical testing regime sounds pretty substantial to me, as far as testing of effectiveness goes.
Are generic drugs tested to ensure their risk of side effects will be roughly equivalent? Or, are there reasons to believe their side effects ought to be equivalent, in magnitude and likelihood? I understand that generics may have different inactive ingredients. Could this cause the risk of side effects to be materially different between versions of the same drug from two different manufacturers? Or is that super-unlikely? Should I discount/ignore concerns about the potential for variation in side effects between manufacturers?
(I do understand that there is a small risk that a patient is allergic to one particular inactive ingredient that's one formulation but not in another, but for purposes of this question, let's ignore that. Apart from that, could there be noticeable, reproducible differences? Or is this unlikely?)
(I have read What can the variability of strength be between different brands of supposedly identical medications?. I know enough statistics to understand why claims that "generics can be up to 45% different in effectiveness" are highly misleading. I've read about studies indicating that the average difference is more like 3% or so, and is probably similar to or smaller than the range of variation among different batches from the same manufacturer. But those seem to be measured by absorption into the blood, and I'm not sure what that implies for the risk of side effects.)