When a Manufactured Medication Is on Back Order: What a 503A Pharmacy Can Prepare

Why clinics ask us this

A patient's manufactured medication is on back order at the wholesaler, the retail pharmacy has none, and your clinic wants to know whether a compounding pharmacy can prepare it in the meantime. We get this call most weeks. The answer depends on one thing: whether that drug is on FDA's drug shortage list at the time it would be compounded. This guide explains the rule, what our pharmacist checks before saying yes, and what to put on the prescription so the order moves on the first pass.

Supply problems are not new to us. Our president and CEO, Jessica Patrone, Pharm.D., talked about compounding medicines during supply chain issues on WJHL's Daytime Tri-Cities back in 2023, and the same questions come up every time a product goes short.

The rule in plain terms

Section 503A of the federal Food, Drug, and Cosmetic Act allows a licensed pharmacy to compound a medication for an identified patient on a valid prescription, but it limits compounding preparations that are essentially copies of a commercially available drug product. Our explainer on what a 503A compounding pharmacy is covers the framework.

The 2018 federal guidance on essential copies draws the line that matters here: a drug product is not treated as commercially available while it appears on the federal drug shortage list at the time the preparation is compounded and dispensed. In practice that gives a prescriber three doors for a patient who cannot get a manufactured product:

1. The product is on the shortage list. A prescriber can write for a compounded preparation for that patient while the product stays on the list.
2. The product is discontinued, or no manufactured version exists. Many preparations clinics order from us have no manufactured equivalent at all, such as estriol or Bi-Est. A discontinued product that is no longer marketed is in the same position.
3. A manufactured product is available, but it does not suit this patient. Then the prescription needs to show the change made for the patient and the difference it makes. Our guide to documenting a significant difference on a 503A prescription covers that door.

If none of the three applies, the prescription belongs at a wholesaler or a retail pharmacy, and we will say so.

"Back ordered" is not the same as "on the list"

This is where most of the confusion sits, so it is worth being precise.

• The federal list is the test, not the wholesaler's screen. A product can be back ordered at one wholesaler, or out of stock at every pharmacy in town, without being on the federal shortage list. The list is public, searchable by drug name, and updated as manufacturers report. Check the FDA drug shortage database before you write.
• ASHP's list is not the same list. The American Society of Health-System Pharmacists tracks shortages too, and its list is often longer. It is useful for planning, but the compounding rule keys off the federal list. Estradiol patches are the current example: patients have had trouble finding them through 2026, ASHP lists them as in shortage, and the federal list does not. Our patient post on estradiol patches being hard to find explains what a prescriber can do instead, which is a different dosage form rather than a copy of the patch.
• The door closes when the shortage ends. Once a product comes off the list, the shortage door is no longer open for the next refill. The prescription then needs one of the other two doors, or the patient goes back to the manufactured product. We watch the list for the preparations we are making under it, and we tell the prescriber when that changes.

What our pharmacist checks before saying yes

A pharmacist reviews every formulation before it is made. Our guide to what the pharmacist checks before a compounded prescription is made covers the full review; for a shortage request, four points decide it:

1. The list entry. The drug, and the presentation named on the list, on the day the preparation would be made.
2. The active ingredient. Each active ingredient has to meet the federal conditions for compounding on its own, regardless of the shortage. A shortage does not make an ineligible ingredient eligible.
3. A source for the ingredient. The pharmaceutical-grade active has to be available to us from a supplier we have qualified. During a widespread shortage the active ingredient itself can be hard to source, and we will tell you if it is.
4. A complete, patient-specific prescription. One named patient, the strength and dosage form your prescriber wants, directions, quantity and refills. A shortage preparation is still made to order for one person after the prescription arrives; nothing is pre-made or held in stock.

If any of the four fails, the pharmacist calls the contact named on the order, explains why, and names the manufactured product or the alternative where one exists.

What to put on the prescription

• Write for the compounded preparation. The strength, the dosage form and the base are your prescriber's decisions. If the patient needs the same strength as the manufactured product, write it; if a different form suits them, write that. Our page on compounding dosage forms explains the forms we prepare.
• Note the reason. A short line such as "manufactured product on the federal shortage list" tells the pharmacist which door the prescription is coming through and goes on the record. If the patient also has a sensitivity, note that too, because it may keep the preparation eligible after the shortage ends.
• Name a contact. One person and a direct line, so a question from the pharmacist is a two-minute call rather than a day's delay.
• Tell the patient what to expect. A compounded preparation is made for them and can look different from the manufactured product they are used to. The label carries the strength and directions your prescriber wrote.

For a program, the planning meetings with our formula development team are where this gets settled ahead of time: which of your standard preparations have a manufactured equivalent, and what the prescription needs to say in each case.

Common questions

Can a compounding pharmacy make a medication that is on back order?

It depends on why it is unavailable. If the drug is on the federal drug shortage list, a prescriber can write for a compounded preparation for a named patient while it stays listed. If it is simply back ordered at a wholesaler but not on the list, the prescription needs one of the other doors: no manufactured version exists, or the prescriber documents a significant difference for that patient.

What is the difference between FDA's shortage list and ASHP's list?

Both track shortages, and ASHP's list is often longer. The compounding rule keys off the federal list, so a product on ASHP's list alone does not open the shortage door. Check the federal database by drug name before writing the prescription.

Can you compound a medication that has been discontinued?

A product that is no longer marketed is not commercially available, so the essential-copy limit does not apply to it. The active ingredient still has to meet the federal conditions for compounding, and we have to be able to source it. Our pharmacist checks both before the prescription is accepted.

Does the patient need a new prescription for the compounded version?

Yes. The prescriber writes for the compounded preparation, including the strength and the dosage form. We prepare what the prescriber writes; we do not prescribe or substitute on our own.

What happens to refills when the shortage ends?

Once the product comes off the federal list, the shortage door closes for the next refill. The prescription then needs a documented difference for that patient, or the patient returns to the manufactured product. We tell the prescriber when a preparation we are making under the shortage rule is affected.

Do you keep compounded versions in stock during a shortage?

No. Every preparation is made for one named patient after the prescription arrives. We have a 48-hour compounding time on most preparations; shipping time is additional and varies by destination.

Ready to set up a program, or to send a single prescription during a shortage? Prescribers can start on our page for prescribers, and clinics and telehealth teams can begin clinic onboarding. ProCompounding is a PCAB-accredited 503A compounding pharmacy in Johnson City, Tennessee, licensed in all 50 states and the District of Columbia.

This article is general information for clinics and is not legal or medical advice. Compounded preparations are not reviewed or approved by the FDA for safety or efficacy.