How Long Can Prescription Drugs Be Stored?

In the realm of preparedness, few questions are as crucial as the longevity of prescription medications. For those stockpiling supplies in anticipation of disruptions—be they natural disasters, pandemics, or other crises—knowing how long medications can be stored safely is essential. The common assumption is that drugs lose their potency right after their expiration date, but decades of research, including that conducted by the U.S. military, suggest otherwise. This article dives into the backstory of this research, including the FDA’s Shelf Life Extension Program (SLEP), and explores how long prescription drugs can be stored effectively.

The Backstory of the SLEP Program

The Shelf Life Extension Program (SLEP) was born out of necessity in the 1980s when the Government Accountability Office (GAO) raised alarms about the $9 million worth of stockpiled medications the military was about to discard simply because they had reached their labeled expiration dates. At that time, there were no alternative measures in place to verify if these medications were still usable, so the standard practice was to dispose of them and purchase replacements. Recognizing the massive financial strain this practice caused, the Department of Defense (DoD) partnered with the FDA to create SLEP in 1986. The goal was simple: test whether medications remained stable beyond their expiration date, allowing the military to avoid unnecessary waste and costs.

What SLEP found was revolutionary. By testing drugs stored under ideal conditions, the program discovered that 88% of 122 different drugs could have their expiration dates extended by at least one year, with an average extension of 66 months. In some cases, medications remained stable for up to 278 months (nearly 23 years). This program became a major cost-saving tool for the military and provided invaluable insights into the longevity of prescription medications.

The SLEP Findings: Key Results

SLEP tested 3,005 lots of various drugs, including widely used medications such as amoxicillin, ciprofloxacin, diphenhydramine, and morphine sulfate injection. The program demonstrated that most solid dosage forms (such as tablets and capsules) retained their potency well beyond their labeled expiration date. The average extension was 66 months, but some drugs, like naloxone, fentanyl, and halothane, were stable for at least 4-5 years after expiration. These findings have changed the way the military and the preparedness community view the shelf life of medications.

Expiration Dates vs. Actual Stability

To better understand how long drugs can be stored, it’s important to recognize what an expiration date actually represents. The expiration date is the point at which the manufacturer guarantees that the medication retains its full potency and safety under normal storage conditions. In reality, many medications remain effective far beyond this date.

According to research, including a 2012 study led by Dr. Lee Cantrell, Director of the California Poison Control System and Professor at the University of California San Diego School of Pharmacy, even medications that were 28 to 40 years old retained 90% of their potency. The Cantrell study analyzed eight medications with 15 different active ingredients, finding that 86% of the substances tested remained stable, despite being decades past their expiration dates. You can find Dr. Cantrell’s research here.

Dr. Cantrell’s Findings on Pain Relievers and Codeine

For those in the preparedness community, pain management is a crucial concern, especially when considering stockpiling over-the-counter (OTC) pain relievers and prescription pain medications like codeine. Dr. Lee Cantrell’s 2012 study, which by way of reminder,  analyzed medications stored for 28 to 40 years in their original, unopened containers, offers significant insights into the longevity of these pain-relieving drugs.

Among the drugs tested were OTC pain relievers and codeine-containing medications. The results revealed that codeine, an opioid commonly used for pain relief, retained 90% of its original potency even after decades past its expiration date. This finding is particularly valuable for preppers, as it confirms that codeine, when stored properly, can remain effective for long periods of time.

Additionally, the study also looked at aspirin, a common OTC pain reliever. While aspirin did degrade more than some of the other compounds tested, it still retained significant potency. The study found that aspirin, along with some other compounds like phenacetin (an older pain-relieving compound), remained stable, though in some instances the potency dropped below 90%. This indicates that while OTC pain relievers may not be as durable as solid forms like codeine, they still retain substantial potency well beyond their labeled expiration date.

For preparedness-minded individuals, these findings are reassuring. While aspirin and other OTC pain relievers may degrade slightly faster than prescription opioids like codeine, both types of medications can remain effective for long periods when stored under optimal conditions.

The Importance of Proper Storage

One of the most important factors in preserving the potency of medications is storage conditions. Drugs are most stable when stored in cool, dry, and dark places. This is why bathrooms, with their high humidity, and cars, with their extreme heat, are poor storage environments. To maximize the shelf life of your medication stockpile, store drugs in tightly sealed containers in a climate-controlled environment. Some medications, such as those that require refrigeration (like insulin), degrade faster if not stored properly.

According to the FDA and other studies, solid dosage forms—tablets and capsules—are the most stable over time. Liquid medications, injectable drugs, and drugs in suspension, however, degrade faster. For example, medications like EpiPens lose their efficacy more rapidly, and the bioavailability of the epinephrine in these devices drops significantly after the expiration date.

Exceptions: Drugs That Should Not Be Used Beyond Expiration

While many drugs retain potency well beyond their expiration dates, certain medications should never be used past their expiration date due to their narrow therapeutic index or susceptibility to rapid degradation. These include:

• Insulin: Degrades rapidly, and sub-potent insulin can lead to dangerously high blood sugar levels.
• Nitroglycerin: Used for heart conditions, it loses its potency quickly.
• Liquid antibiotics: These should not be used past expiration as they may not effectively treat infections, leading to complications or antibiotic resistance.

Similar Results from Veterinary Medications

Interestingly, similar results have been found when testing veterinary medications, which are often identical to human drugs. Research has shown that many vet medications, when stored properly, retain their potency well beyond their labeled expiration dates. This adds further credence to the idea that many drugs are formulated to last much longer than the dates printed on their packaging suggest.

Civilian Access to SLEP Data

While the SLEP data offers a wealth of information about the stability of medications, access to the full findings is restricted to military and government entities. As a civilian, I have spent countless hours poring over the hundreds of articles, studies, and references made available through secondary sources that report on the SLEP findings. Though I don’t have direct access to the raw data, by piecing together this information, I’ve been able to glean valuable insights that can help those in the preparedness community make informed decisions about stockpiling medications.

How Long Can Prescription Drugs Be Stored?

Based on the findings from both U.S. and European research, including the extensive work done by the SLEP and Dr. Cantrell’s study, many prescription medications, particularly solid forms like tablets and capsules, remain stable and effective well beyond their expiration dates. Under proper storage conditions, many drugs retain 90% of their potency for years after expiration. The SLEP findings showed that some drugs could last for up to 23 years with proper storage.

However, certain medications, particularly those in liquid or injectable form, degrade more quickly and should not be relied upon after expiration. Preparedness-minded individuals should focus on stockpiling stable medications, ensuring proper storage, and periodically reviewing stock for signs of degradation.

For further reading, you can access Dr. Lee Cantrell’s study here. And for additional information on the FDA’s Shelf Life Extension Program, visit the official page here.