Allergy medications, commonly known as antihistamines, alleviate symptoms of allergic reactions by blocking histamine, a chemical the body releases in response to allergens. These medicines come in various forms, including pills, liquids, nasal sprays, and eye drops. Every medication, whether prescription or over-the-counter, carries an expiration date printed on its packaging. This date signifies the period during which the manufacturer guarantees the product’s full strength and quality, assuming it has been stored under recommended conditions.
Diminished Efficacy
The most common outcome of consuming expired allergy medicine is a reduction in its effectiveness. Over time, the active ingredients in medications undergo chemical degradation, leading to a decrease in their potency. This means the medicine may not provide the intended relief for allergy symptoms such as sneezing, itching, or a runny nose, or the relief may be incomplete or delayed. For instance, expired Zyrtec, an antihistamine, may not work as well as expected, potentially leaving symptoms unmanaged.
This decline in potency occurs because the chemical structure of the active pharmaceutical ingredients (APIs) can change, making them less capable of interacting with the body’s systems to produce the desired therapeutic effect. While solid forms like tablets and capsules generally exhibit more stability past their expiration date, liquid medications, including many allergy syrups or eye drops, are more susceptible to losing potency. Relying on a sub-potent medication for allergy relief can mean a person’s symptoms persist, potentially leading to discomfort or even a worsening condition if not adequately addressed.
Safety Considerations
While a loss of effectiveness is the primary concern, taking expired allergy medicine can also carry potential, though less common, safety risks. As active ingredients degrade, they can sometimes form new chemical compounds, some of which might be harmful or toxic. The unpredictability of these degradation products is a concern, as their effects on the body are unknown. Although specific instances of allergy medicines becoming toxic upon expiration are rare, the chemical stability of different active ingredients varies.
For example, certain types of medications, particularly liquid formulations, may become susceptible to bacterial growth once expired, which could pose a health risk. The U.S. Food and Drug Administration (FDA) advises against using medications beyond their expiration date due to these potential risks, emphasizing that there is no guarantee of safety or effectiveness once that date has passed.
Factors Influencing Medication Stability
Medications degrade over time due to various environmental factors that can accelerate the breakdown of their chemical components. Exposure to high temperatures, humidity, and light are significant contributors to chemical degradation. For example, heat can speed up chemical reactions, leading to impurities and reduced potency. Light, especially ultraviolet light, can degrade drug molecules. Humidity can cause physical changes like caking or softening, and promote chemical reactions.
Inactive ingredients, known as excipients, are also formulated into medications to help maintain their stability up to the expiration date. Excipients can protect the active ingredient from degradation by external factors, manage moisture, and shield against light.
Managing Expired Medications
It is generally advised not to use expired medications, including allergy medicines, due to the potential for diminished effectiveness and possible safety concerns. The safest and most environmentally responsible way to dispose of unused or expired medications is through drug take-back programs. Many communities offer these programs at local pharmacies, police stations, or through periodic take-back events organized by entities like the U.S. Drug Enforcement Administration (DEA). These programs ensure proper disposal, preventing medications from entering the water supply or falling into the wrong hands.
If a take-back option is not readily available, most medications can be disposed of in household trash. To do this safely, remove the medication from its original container and mix it with an undesirable substance like used coffee grounds, dirt, or cat litter. This mixture should then be placed in a sealed plastic bag before being put in the trash, making it less appealing to children or pets. It is important to avoid flushing most medicines down the toilet unless specifically instructed on the label, as this can lead to water pollution. If you have accidentally taken expired medication and experience unusual symptoms, or have concerns, consulting a healthcare professional or pharmacist is recommended.