When a pharmacist hands you a bottle of compounded medication, it doesn’t come with a manufacturer’s expiration date like the pills you get at a regular pharmacy. Instead, it has a beyond-use date - or BUD. This isn’t just a label. It’s a safety deadline. If you use the medication after this date, you’re risking reduced effectiveness, chemical breakdown, or even dangerous contamination. Unlike FDA-approved drugs tested for years before hitting shelves, compounded medications are made one batch at a time, often for patients with unique needs. That’s why getting the BUD right matters more than you think.
What Exactly Is a Beyond-Use Date?
A beyond-use date is the last day a compounded medication is considered safe and effective to use. It’s calculated from the day it was made, not when you picked it up. This date is set by the pharmacist who prepared it, based on science - not guesswork. The US Pharmacopeia (USP) Chapter <797> sets the rules for this, and the FDA requires all compounding pharmacies to follow them.
Think of it this way: a factory-made drug like aspirin has been tested under every condition - heat, humidity, light, time - for years. Its expiration date is backed by real data. A compounded medication? It might be a custom liquid version of a pill, mixed with a flavoring, stored in a plastic syringe, and meant to last two weeks. No one’s tested that exact mix before. So the BUD has to be based on the best available evidence - and sometimes, that’s not enough.
Why BUDs Are Different From Expiration Dates
Expiration dates on commercial drugs are guaranteed by the manufacturer. They’re based on stability testing that can take years. Compounded medications don’t get that luxury. They’re made in small batches, often with altered ingredients, strengths, or delivery methods. A pill turned into a liquid? A hormone cream with a different base? A steroid injection without preservatives? Each change affects how long the drug stays stable.
Studies show compounded formulations with altered pH levels degrade up to 3.7 times faster than their commercial versions. That means a BUD for a custom liquid might be just 14 days - even if the original pill lasts years. The container matters too. Glass vials protect better than plastic syringes. But many pharmacies still assign BUDs for syringe-stored meds using data meant for vials. That’s a problem. The FDA has warned that syringes aren’t approved for long-term storage. Yet, over 40% of retail compounding pharmacies still do it.
How Pharmacists Determine a BUD
Assigning a BUD isn’t arbitrary. There’s a process. USP <797> allows four methods:
- Use the manufacturer’s stability data for the raw drug
- Consult the drug’s original FDA-approved labeling
- Check published scientific literature
- Run direct stability testing
The gold standard? Direct testing. That means taking the actual compounded batch, storing it under real conditions, and testing it over time to see if the active ingredient breaks down or microbes grow. High Performance Liquid Chromatography (HPLC) is the go-to tool. But here’s the catch: only about 37% of compounding pharmacies use properly validated HPLC methods. Most rely on literature or manufacturer data - which might not match their exact formula.
For example, if a pharmacist makes a liquid version of a painkiller using a different preservative, the degradation rate could change by 63%, according to a 2021 study. That’s why using data from a different formulation is risky. The only truly reliable BUD comes from testing the exact mix, in the exact container, under the exact storage conditions.
What Determines How Long a BUD Lasts
Not all compounded medications are the same. USP <797> classifies them into three risk levels:
- Low-risk: Simple mixtures, like saline with one drug, made in a clean area. BUD: up to 48 hours at room temperature, or 14 days if refrigerated.
- Medium-risk: More complex, like adding multiple drugs or using non-sterile ingredients. BUD: up to 30 hours at room temperature, or 30 days if refrigerated and tested.
- High-risk: Involves non-sterile components or prolonged exposure. BUD: max 24 hours, even if refrigerated.
Water-based formulas are especially tricky. They’re prone to mold and bacteria. Before December 2023, their BUD was capped at 14 days. Now, with proper testing, it can be extended to 30 days. But that’s only if the pharmacy actually runs the tests - and most don’t.
Storage is just as important. A BUD for a refrigerated medication doesn’t apply if you leave it on the counter. Temperature, light, and humidity all play a role. A hormone cream stored in a hot bathroom? It might lose potency in days.
Common Mistakes That Put Patients at Risk
Pharmacists aren’t trying to cut corners. But the system is stacked against them.
First, there’s a lack of data. Over 60% of compounding pharmacists say they can’t find published studies for their exact formula. So they guess. They stretch a BUD from a similar product. They assume a plastic syringe works like a glass vial. They ignore container interactions - which, according to former USP committee chair Dr. Robert G. Smith, cause 68% of BUD errors.
Second, documentation is often missing. Federal law requires written justification for every BUD. Yet, many pharmacies don’t keep it. In 2023, 47 states required specific documentation formats. But compliance? Only 77% in retail pharmacies. Hospital pharmacies do better - 92% - because they have more resources.
Third, some pharmacists extend BUDs without testing. The FDA issued 15 warning letters in 2022 alone for this. One pharmacy had to recall over 1,200 products because BUDs were too long - and the meds were contaminated with bacteria. Patients got sick. That’s not hypothetical. It happened.
What You Should Do as a Patient
You’re not expected to be a pharmacist. But you can protect yourself.
- Ask: “What’s the beyond-use date, and how was it determined?” If they say, “It’s standard,” push back.
- Check the container. Is it a syringe? A plastic bottle? Glass vial? Ask if the BUD was set for that specific container.
- Store it correctly. If it says “refrigerate,” keep it cold. Don’t leave it in a car or on a sunny windowsill.
- Don’t use it after the BUD. Even if it looks fine. Degradation isn’t always visible. The drug might still look clear, but 30% of its potency could be gone.
- Ask if stability testing was done. If they say no, consider going to a hospital-based compounding pharmacy or one that’s accredited by PCAB (Professional Compounding Centers of America).
Compounded meds are lifesavers for people allergic to dyes, needing custom doses, or requiring drugs no longer made. But they’re only safe if the BUD is accurate. Don’t assume it’s fine. Ask questions.
The Future of BUDs: Testing, Tech, and Tighter Rules
The compounding market is growing fast. It’s expected to hit $12.7 billion in 2023 - and could be 18% of all prescriptions by 2030. That means more people relying on these meds. And more risk if BUDs aren’t handled right.
USP is pushing for change. Their 2024 draft says any BUD longer than 30 days must be backed by direct stability testing. That’s a big shift. Right now, 24% of compounded meds have BUDs longer than that. Most of those aren’t tested.
Some pharmacies are already using new tech. Epicur Pharma’s SmartBUD system monitors real-time stability. In a 2023 pilot, it cut BUD errors by 47%. That’s not science fiction - it’s here.
The message is clear: BUDs aren’t just labels. They’re safety tools. And as personalized medicine grows, getting them right will be non-negotiable.
Is a beyond-use date the same as an expiration date?
No. An expiration date is assigned by a manufacturer after years of testing and is legally guaranteed. A beyond-use date (BUD) is assigned by a compounding pharmacist based on scientific data, literature, or testing - and applies only to custom-made medications. BUDs are typically much shorter and are not FDA-verified.
Can I use a compounded medication after its beyond-use date if it looks fine?
No. Even if the liquid is clear or the cream hasn’t changed color, the active ingredient may have degraded. You could be getting less than half the intended dose - or worse, the medication could be contaminated with bacteria or mold. Never use a compounded medication past its BUD.
Why do some pharmacies give longer BUDs than others?
It depends on their methods. Pharmacies that do direct stability testing can assign longer BUDs - up to 30 days for refrigerated water-based formulas. Others rely on literature or manufacturer data, which may not match their exact formula, leading to shorter or inaccurate BUDs. Hospital pharmacies usually have more resources for testing, so their BUDs are more reliable.
Are syringes safe for storing compounded medications long-term?
No. Syringes are not approved for long-term storage. They’re designed for single use. Plastic syringes can leach chemicals, and their seals aren’t designed to prevent contamination over days or weeks. Yet, over 40% of retail pharmacies still assign BUDs based on vial data - even when the drug is stored in a syringe. This is a major safety risk.
How can I tell if a compounding pharmacy is reliable?
Look for accreditation from PCAB (Professional Compounding Centers of America) or ACHC. These organizations require strict adherence to USP <797> standards, including documented BUD assignments and stability testing. Ask the pharmacy if they perform direct testing and if they keep written records for each BUD. If they can’t provide that, consider another provider.
