Short answer first, then the reasoning. 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.
Two pharmacies quoted me last year, one describing itself as 503A and one as 503B, and I assumed 503B just meant bigger until both stopped within weeks of each other.
What I am after is why a shortage listing created a legal pathway at all, since a shortage is a supply fact rather than a permission.
Happy to be told the question itself is wrong.
TirzTom said:The shortage clause is the answer to the second question and it is a subtraction rather than an addition.
Agreeing with TirzTom, and the qualification matters more than the agreement. 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.
If somebody has the primary source to hand I would rather cite it than paraphrase it.
Sigma-Aldrich — Research-Grade Standards
Certified reference materials, analytical reagents, and research-grade standards for peptide verification. Trusted by laboratories worldwide.
Shop Reference StandardsPedsEndoPhilly said:Two pharmacies quoted me last year, one describing itself as 503A and one as 503B, and I assumed 503B just meant bigger until both stopped within…
This matches mine closely enough to be worth saying so. They are two different exemptions from the same federal requirements and they buy different things. A 503A pharmacy is regulated primarily by the state board, needs a patient-specific prescription, is exempt from CGMP, and may use a bulk substance that has a USP monograph, is a component of an approved drug, or appears on the 503A bulks list — three independent doorways. A 503B outsourcing facility registers with the FDA, is inspected on a risk basis, must comply with CGMP, may compound for office stock without a patient-specific prescription, and has one doorway to a permitted bulk substance: the 503B bulks list, or the drug shortage list.
From the other side of the consultation, briefly.
I have been on both brand and compounded, and in the context of compounded supply, my experience has been equivalent with both. The key is finding a reliable 503B pharmacy with independent testing.