bri_stats said:

Steady state is the thing most people miss.

Agreed, and the enforcement dates were staggered by category — 503A first, 503B a few weeks later — because outsourcing facilities have manufactured inventory and clinic contracts to unwind while a 503A makes to order.

bri_stats said:

Steady state is the thing most people miss.

This is exactly what I could not find anywhere else. I will report back once I have actually tried it.

Clinical perspective, offered as context rather than as advice. Start from the measurement rather than the conclusion. Almost every disagreement here turns out to be two people measuring different things and comparing the numbers anyway.

Dr.SurgeonPGH said:

Start from the measurement rather than the conclusion.

Same position here, arrived at the long way round. Worth adding the genuine exception, because it is real and narrow: a change made for an identified patient where the prescriber determines it produces a significant clinical difference for that patient. A grid of fixed doses offered to everybody is not that, whatever the intake form says.

Dr.SurgeonPGH said:

Start from the measurement rather than the conclusion.

Coming at Dr.SurgeonPGH’s question from a different direction. The shortage clause is the answer to the second question and it is a subtraction rather than an addition. Both exemptions forbid compounding something that is essentially a copy of a commercially available approved product. A product FDA has listed as in shortage is not treated as commercially available, so listing removed the objection that otherwise blocked compounding. It never created a permission; it withdrew a prohibition, which is why it evaporated the moment the supply fact changed.