In Part I of this series, I explained the definition of pharmaceutical expiration dates and ‘do not use beyond’ dates, and how both are determined. Additionally, I reviewed information from the Shelf Life Extension Program (SLEP) database, which led to a temporary Emergency Use Authorization in 2009, permitting the use of certain Tamiflu products (to treat H1N1 influenza) for up to an additional five years beyond the imprinted expiration date. (See Part I of this series for more information. )
Part II will examine the data regarding use of common antibiotics beyond their expiration dates.
The following is excerpted from my upcoming book, Armageddon Medicine.
Does a can of tuna go bad overnight? What about a bottle of medicine? Common sense suggests the answer is no, but is there any evidence?
The primary source of information regarding the prolonged stability of medications comes from the Shelf Life Extension Program database. Rather than discard millions of dollars worth of expired drugs stockpiled for emergency use, the U.S. federal government tested representative lots of selected medications for extended stability. These stockpiled drugs are aimed at emergency use for injuries and infections rather than chronic diseases such as diabetes, heart disease, and asthma. The most useful data for the layman is related to drugs to combat bacterial and viral infections.
Of the antibiotics tested, all passed assays for stability, potency, and appearance for at least a year beyond the original expiration date.
Of the lots tested, the following had their expiration date extended by the number of months indicated.
| Medication Name | Dosage Form | Average extension in months (range) |
| Amoxicillin sodium | Tablets | 23 (22-23) |
| Ampicillin | Capsules | 49 ( 22-64) |
| Cephalexin | Capsules | 57 (28-135) |
| Ciprofloxacin | Tablets | 55 (12-142) |
| Doxycycline Hyclate | Capsules | 50 (37-66) |
| Erythromycin lactobionate | Powder | 60 (38-83) |
| Sulfisoxasole | Tablets | 56 (45-68) |
| Tetracycline HCl | Capsules | 50 (17-133) |
| Silver sulfadiazine | Cream | 57 (28-104) |
A summary of the Shelf Life Extension Prorgarm (SLEP) data is available in The Journal of Pharmaceutical Sciences, Vol. 95, No. 7, July 2006.
The Medical Letter, a respected professional newsletter, addressed the topic of expired medications in both 1996 and 2002. Regarding safety, they say: “The only report of human toxicity that may have been caused by chemical or physical degradation of a pharmaceutical product is renal tubular damage that was associated with use of degraded tetracycline. . . Current tetracycline preparations have been reformulated with different fillers to minimize degradation and are unlikely to have this effect.” (The Medical Letter, Vol. 44, Issue 1142, October 28, 2002.)
Liquid preparations may be much less stable, and degrade more quickly if frozen or heated. The Medical Letter advises that “Drugs in solution, particularly injectables, that have become cloudy or discolored or show signs of precipitation should not be used.” For oral medications, color changes may also be related to the dyes rather than the drugs. The primary concern pertaining to eye drops is microbial contamination once the preservative becomes ineffective.
Overall then, the concern is not regarding safety, but rather effectiveness. “Many drugs stored under reasonable conditions retain 90% of their potency for at least 5 years after the expiration date on the label, and sometimes much longer,” per The Medical Letter.
The SLEP data does not describe testing for any controlled-release antibiotics, such as Biaxin XL and Augmentin XR. Controlled-release delivery systems vary from drug to drug and would require testing not only of the medication itself, but the delivery system as well, to assure adequate drug delivery. Therefore, the regular versions of both Biaxin and Augmentin may be preferable for stockpiling. Essentially the only advantage of controlled-release antibiotics is less frequent dosing.
In the case of antibiotics, a 10-25% loss of potency over time may make little difference in treatment, and could be made up for by higher dosing in serious infections. Even now, generic medications are only required to be within 20% of the stated amount, and so the dose administered may already vary as much as 50% from one generic to another, or from pill to pill. For example, a 100 mg brand-name tablet must contain 95-105 mg of the active drug, whereas a generic of the same is permitted to have 80-125% active compound. Also, generics may not be equivalent in terms of integrity, dissolution properties, or coatings. In the case of generics, “Made in the USA” is probably preferable to those manufactured elsewhere.
To sum it all up, the good news is that most tablets and capsules are very likely safe and quite likely effective for several years beyond the printed expiration date. Using expired medications may suffice for a decade beyond the end of the world as we know it. (But what then?)
In my next post I will examine the use of other common drugs beyond their expiration date. – Cynthia J. Koelker, MD.
About The Author: Cynthia J. Koelker, MD is the author of the book 101 Ways to Save Money on Health Care. The book explains how to treat over 30 common medical conditions economically, and includes dozens of sections on treating yourself. Available for under $10 online, the book offers practical advice on treating: respiratory infections, pink eye, sore throats, nausea, diarrhea, heartburn, urinary infections, allergies, arthritis, acne, hemorrhoids, dermatitis, skin infection, lacerations, lice, carpal tunnel syndrome, warts, mental illness, asthma, COPD, depression, diabetes, enlarged prostate, high blood pressure, high cholesterol, and much more.
Dr. Koelker has recently started a new medical blog on surviving TEOTWAWKI, ArmageddonMedicine.net. She welcomes your questions, comments, and critiques.