Well, testing is still needed to determine the appropriate dosage. If the dosage is lower or identical to the prescription drug, it's all good. If it ends up being much higher, this may be a big problem.
So to clarify: it can be tested directly on patients now, in the dosage it’s already approved for in previous trials, without the need for (or at the same time as) formal trials?
And this should be the case for most such existing drugs?
Or are drugs only approved for specific uses so doctors can’t do this?