Once drugs lose patent protection, it's difficult for them to gain approval for new indications, because drug approval procedures are extremely expensive and there's no patent holder left for whom it would make economic sense to spend all that money.
So in cases like valproate for migraine, those drugs usually stay off-label long term. That makes them unattractive for doctors to prescribe, since they assume more liability if something goes wrong, and insurance companies are less likely to cover the drugs.
The way information about off-label uses gets communicated is basically the same way as elsewhere in science: through scientific papers, conferences, textbooks, and the like. A doctor who discovers that their migraine patient does well on valproate might publish this as a case report. If there are many such reports, someone might do a randomized trial. Once there are many randomized trials, meta-analyses can be performed, and eventually, the information will end up in textbooks and medical school curricula.
It takes a certain amount of agency for a doctor to stay up to date on the latest research; while medical boards tend to have certification requirements for CME (continuing medical education), these are usually quite lax, and a truly lazy doctor can probably just live their years without really learning anything new.
At the same time, reading all new research that comes out is basically impossible, and even just trying to do this would risk always following the latest fads that later evidence might show to, in fact, be harmful. Every doctor needs to find their own middle ground here, and you as a patient must find a doctor that suits your own preferences.
> Once drugs lose patent protection, it's difficult for them to gain approval for new indications, because drug approval procedures are extremely expensive and there's no patent holder left for whom it would make economic sense to spend all that money.
This is precisely why I think a gov't run research effort is the right way to handle this. You don't want to grant a new patent on the existing drug just because of new use of it. That would prevent the generics being used for the original purpose. So if the bigPharma company that created it for original purposes does not want to spend money researching alternate uses, then allow the gov't direct the research in the name of keeping its citizens healthy.
Unfortunately, that doesn't really stand up as a great solution with using the current administration as an example of what happens when you get anti-science mindsets in charge of things. It also helps to have a gov't that is empathetic for its citizens which does not always happen.
Yes, in fact, most of the types of research I mentioned, where random people at hospitals do small trials on existing medications, is going to be partially government funded.
But care must be taken to avoid the tulip subsidies problem [1]: the barriers to drug approval are regulatory, not natural. If a drug regulatory agency sets high requirements for approval and another governmental agency must do expensive work to satisfy these requirements, there is a risk that costs go out of control without any real benefit.
Instead, my favoured solution would be to significantly relax regulatory requirements in cases like this where a drug has already been proven to be safe both in the original approval trials and in years of real-world use, such that when trials and meta-analyses exist that suffice to convince the medical establishment of a drug's safety and efficacy for a new indication, these would also be enough for the drug to gain approval for that indication.
[1] https://slatestarcodex.com/2015/06/06/against-tulip-subsidie...
I wonder if some sort of coalition of compounding pharmacists might be up for making and retaining a repository. They at least make some money by helping would-be patients take these drugs, right? So even if it's nothing like Big Pharma money, I can't really think of anybody who'd have a better chance to benefit from promoting off-label use cases for out of patent drugs than them.
Yes, but why be the one to set it up? Why not be the pharmacist who waits for others to do it, and then sell it anyway?
...sell ads on it? Maybe for the docs who are willing to prescribe off-label? Maybe for other pharmacies?
I don't know. Maybe it's not a viable business model, but there are certainly weirder things that make money.