With a migraine headache threatening, reach for Imitrex, the prescription drug that brings these debilitating headaches to a screeching halt. The pharmacy label warns: "Discard after February 2005." Those tiny tablets cost $16 each, almost their weight in gold.
Can you still take it in May? Ask the same questions for scores of other prescription drugs, which cost people in the United States more than $160 billion annually.
The expiration dates on jugs of milk and cartons of yogurt tell consumers when a product goes bad. That may not always be true with the labels on prescription drugs, according to research that includes a little-known government testing program.
Government tests have found that some drugs stay fresh for years longer, enabling the military to save millions of dollars in replacing "expired" drugs. While the American Medical Association has urged the pharmaceutical industry to see if consumers are wasting money by pitching drugs that are still safe and effective, nothing has been done.
The research raises questions about how seriously consumers should take expiration dates on some medicines but leaves them without key information to make decisions, according to Dr. Stephen R. Byrn, an expert on drug stability at Purdue University.
"A consumer really needs to know what they are doing to take a drug that has expired," Byrn said. "In most cases the data to support using drugs past their expiration date is not available, so, of course, consumers would not be able to get this information."
In dispensing pills, pharmacists use the manufacturer's expiration date to pick the "discard after" or "beyond-use" date they put on prescription labels. It can't exceed the manufacturer's expiration date, and usually is shorter. If the manufacturer says Prozac, Viagra, Cipro, Ambien, or Valium expires in May 2006, patients might get a prescription bottle labeled "Discard after May 2005."
The Shelf Life Extension Program (SLEP), however, has found that drugs can stay safe and effective long after the manufacturer's expiration date if properly stored in the original container. Run by the federal Food and Drug Administration for the Defense Department, it has saved the military millions of dollars on replacement of "expired" drugs.
"This program is a large cost saver to the taxpayer," said Ellen M. Kavanagh, an assistant manager of the shelf-life program. In one instance, the Pentagon spent about $350,000 on testing of supposedly expired drugs, and avoided needlessly discarding about $33 million worth of medicine.
Dr. Robbe C. Lyon, deputy director of product quality research at the FDA, said consumers should pay attention to expiration dates on their drug bottles because shelf-life program's findings apply to drugs stored in the original containers under ideal conditions.
"But once the container is opened and exposed to an unpredictable environment, it is difficult to predict the drug effectiveness," Lyon said. "For patients who rely on medications to stay alive, like heart medications, expired drugs can be dangerous because they may not be getting the full effectiveness of the drug."
Other studies, however, suggest that some prescription drugs in the bottles given to patients, stored under ordinary household conditions, also are surprisingly durable. They may remain fresh beyond the "discard after" date.
The Medical Letter, a respected source of independent information about drugs, covered the topic in a 2002 article. It reported that certain medicines, stored in high humidity and other bad conditions, stayed good to use for 1.5 to nine years after their expiration dates. For instance, Symmetrel (amantadine) and Flumadine (rimantidine), anti-viral drugs used to prevent and treat influenza, withstood 160-degree temperatures and were good after the equivalent of 25 years of ordinary storage.
"Many drugs stored under reasonable conditions retain 90 percent of their potency for at least five years after the expiration date on the label, and sometimes much longer," the report stated.
Nobody knows for sure, because a consumer-oriented version of Pentagon shelf-life program -- which would check the actual life span of prescription drugs stored in bathrooms, kitchens, purses, and cars -- has never been done.
"Currently, I am not aware of any programs that focus on drug stability in the consumer environment," said Dr. Claudia Okeke, an associate director at the U.S. Pharmacopeia in Rockville, Md. Pharmacopeia is a nonprofit private organization that establishes standards for stability, purity, and quality of medicines and is the source of the USP symbol found on medications.
Overly conservative expiration and discard-after dates could make consumers waste money by throwing away good drugs. On the other hand, taking stale medicine that doesn't work could make diseases get worse.
Contrary to common belief, there is little scientific evidence that expired drugs are toxic. The Medical Letter could find just one reported case in which a patient may have been harmed by taking an expired drug. It occurred more than 40 years ago and involved a patient who may have suffered kidney damage from taking expired tetracycline, an antibiotic. Since then, tetracycline products have been changed to eliminate the problem.
With doctors confused about what to advise patients, the AMA in 2001 urged that the pharmaceutical industry study the medical and financial implications of expiration dating.
"The actual shelf life of many pharmaceutical products might be considerably longer than the expiration date that appears on the manufacturer's container, which could result in unnecessary waste, higher pharmaceutical costs, and possibly reduced access to necessary drugs for some patients," the AMA's Council on Scientific Affairs said.
One group of patients would benefit most by lengthening expiration dates.
They use medication prescribed on a "take-as-needed" basis. Patients take a pill only when symptoms appear, or get worse, and pills may sit unused for months at a time. Such drugs include pain medicines; migraine drugs like Imitrex; sleeping aids like the best-seller, Ambien; male impotence drugs like Viagra, Levitra, and Cialis; allergy drugs; some anti-anxiety drugs; and anti-viral medicines intended for use only if influenza outbreaks occur.
Nitroglycerin, the heart drug, is one take-as-needed drug known to have a very short shelf life after the bottle is unsealed. Liquid medicines also have short shelf lives.
Other patients also may switch from one medicine to another and then back to the original drug, or take medication breaks that leave pills sitting unused.
There are wider implications, as well, since some international aid agencies and foreign countries refuse donations of desperately needed drugs for AIDS and other serious diseases if the medication is expired or nearing the expiration date.
AMA called on the pharmaceutical industry, including the Pharmaceutical Research and Manufacturers of America (PhRMA), to determine whether increasing expiration dates would save money and involve any risks for patients. PhRMA is the main pharmaceutical industry trade group.
"A letter was sent to PhRMA simply urging them to share the Council on Scientific Affairs report with its member companies to determine whether longer expiration dates would provide any economic or clinical benefits for patients," the council's Nancy Nolan said. The AMA got no answer, she added.
Dr. Alan Goldhammer, a vice president for regulatory affairs at PhRMA, said he could not easily determine whether the association carried through on the recommendation. He disputed any implication that the pharmaceutical industry uses conservative expiration dating to increase sales by making consumers discard good medication.
"Companies choose a conservative approach so that patients will receive drugs that are safe, pure, and potent under the conditions of storage," he said.
The first hints that manufacturers understate actual expiration dates, causing good medicine to be thrown away, emerged in the 1980s.
As part of President Ronald Reagan's efforts to increase military readiness, the Defense Department amassed a $1 billion stockpile of drugs and medical devices. By 1985, many of them were nearing the expiration date, and the Pentagon faced a huge bill for buying replacements.
The Pentagon wondered if the drugs really were going bad, and asked FDA to test them with the same "stability" tests manufacturers perform before marketing a drug.
Manufacturers use various tests to see how long drugs remain "stable" and good to use. The chemicals in a medicine break down over time with exposure to humidity, heat and light. They gradually become unstable, changing into new forms that don't work like the fresh ingredients.
Some stability tests speed up the clock by subjecting drugs to high humidity, heat and other harsh conditions for a few months. The results allow scientists to project how long a drug will remain stable under ideal conditions. Other tests monitor drugs stored for long periods under real-world conditions.
Most drugs have expiration dates 12 to 60 months after manufacture, according to PhRMA.
The shelf-life program found that manufacturers use conservative expiration dates. About 85 percent of the Pentagon's drug stockpile remained good after the expiration date, and shelf-life program extended their expiration dates by an average of 57 months, according to the FDA. Among them were everyday antibiotics like tetracycline and penicillin; the tranquilizer Valium (diazepam); and the ulcer drug, Tagamet (cimetidine). One batch of the antibiotic Cipro (ciprofloxacin) was good 13 years after the expiration date.
The testing did not include liquid medicines, vaccines, blood products, and other items known to spoil.
The shelf-life program's Kavanagh described the testing as comprehensive and scientifically sound. "Each item is stressed, placed in a chamber which maintains a temperature of 122 degrees and 75 percent humidity for 60 days," she explained. "The potency of the stressed samples is compared with the standard for each item, and using the comparison, the FDA estimates the extendable life of the product."
Kavanagh also emphasized that the extensions apply only for medicine stored in military depots. "Individual prescriptions issued to patients are never considered for extension," she said, "since the storage conditions of these items by individuals cannot be assured."
She estimated that the shelf-life program saves the Defense Department $75 to $100 for every dollar spent on testing.
That program now is helping to save money on replacing tons of life-saving drugs in government stockpiles maintained for terrorist attacks, flu epidemics, nuclear power plant accidents and other civilian public health emergencies.
Like USP's Okeke, spokesmen for several pharmaceutical companies said they were unaware of any other programs to test actual shelf lives of prescriptions dispensed to patients.
Although health insurers spend heavily on prescription drug benefits, they have not joined the AMA in urging such a program. Spokesmen for Aetna and Wellpoint, for instance, did not even respond to requests for comment.
Dr. Robert J. Weber, chairman of pharmacy and therapeutics at the University of Pittsburgh school of pharmacy and executive director of pharmacy and therapeutics at the University of Pittsburgh Medical Center, said there could be significant savings.
"The kind of research suggested by the AMA should be done and could save consumers and insurers money, considering the high cost of prescription drugs," Weber said. "Putting the results into effect, however, might take a lot of consumer education to avoid situations like hoarding drugs and using medications that are no longer necessary for them."
Michael Woods can be reached at email@example.com or 202-662-7072.