Expiration date of medications

Many medications do not come with a shelf life or expiration date obtainable from a pharmacist. It is assumed medications used in the relatively short time frame for which is is prescribed. That is not the case for MP patients whose antibiotics may last past a listed date.

Some pharmaceutical companies have supported initiatives for patients to discard medications if there is any doubt about safety or efficacy, because it may have expired. While research suggests that properly stored medications merely lose potency over long periods of time, it is not recommended that patients take medications past their expiration date. To prolong both their safety and efficacy, all Marshall (MP) medications should be stored in a cool, dry location.

Effective shelf life

The shelf life of medications is a matter of dispute with no clear answer. A large study of medications stockpiled by the military for decades revealed that most had not lost potency and were still safe well past the manufacturers expiration dates1). There were only a few (insulin, nitroglycerin and liquid antibiotics) that lost potency. None were deemed unsafe. A Medscape article reviews this study and others in greater detail.

Although older medication may be safe to take, in this litigious society, no medical professional is going to suggest a patient takes any medication that is listed as expired.

Exposure to moisture

With regard to minocycline, the medication does not appear to degrade in air via oxidation – only water in a process known as hydrated oxidation. This is a problem with all the other MP antibiotics as well. One complication of taking antibiotics stored in a moist environment is Fanconi syndrome.

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  • Legacy content

NEW STUDY: Patients ask all the time about the effectiveness and safety of “expired” drugs. A recent article that appeared in the Medical Letter examines the issue in detail. The article notes that generally manufacture expiration dates merely reflect the fact that the drug is “stable” at that point, they do not reflect when the drug becomes unstable. The conclusion of the article indicates that outdated drugs may be effective and safe for at least 5 years after the expiration.

Notable exceptions include liquid suspensions and epinephrine in Epipen, which are not stable over time.

The article also notes the following: “ There are no published reports of human toxicity due to ingestion, injection or topical application of current drug formulations after their expiration date. Renal tubular damage has been reported after use of degraded tetracycline in a formulation that is no longer available (REF 2).” Other sources contain warnings about expired doxycycline, which may (or may not) be based on this outdated tetracycline warning, but patients may want to check with their doctors when using expired doxycycline to be on the safe side.

The article concludes:

When no suitable alternative is available, outdated drugs may be effective, and there is no indication that they are not safe. There are no reports of toxicity from degradation products of currently available drugs. How much of their potency they retain varies with the drug, the lot and the storage conditions, especially humidity, but many drugs stored under reasonable conditions in their original unopened containers retain 90% of their potency for at least 5 years after the expiration date on the label, and sometimes much longer.

A copy of the article is here: https://www.medicalletter.org/freedocs/expdrugs.pdf

===== References =====

Taylor JS, Lyon RC, Prasanna HR, Hussain AS. Stability profiles of drug products extended beyond labeled expiration dates. Program and abstracts of the 2002 FDA Science Forum; February 20-21, 2002; Washington, DC. Poster Abstract, Board AC-08. Available at: https://www.cfsan.fda.gov/~frf/forum02/a109ac8.htm. Accessed April 8, 2004
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