Pink eye, or conjunctivitis, is a common eye condition characterized by inflammation of the conjunctiva, the membrane lining the inside of your eyelids and the white part of your eyeball. When faced with symptoms like redness, itching, and discharge, many people reach for eye drops. A frequent question arises regarding the safety and effectiveness of using eye drops that have passed their expiration date, especially for a condition like pink eye.
Why Medications Expire
Medication expiration dates are not arbitrary; they reflect the manufacturer’s guarantee of a product’s safety and full potency until that time. Over time, the active ingredients in eye drops can degrade, losing their intended strength and effectiveness. This degradation can be influenced by factors like exposure to air, light, and temperature fluctuations.
The breakdown of preservatives within the eye drop solution also contributes to expiration. Preservatives, such as benzalkonium chloride (BAK), are included to prevent the growth of bacteria and fungi once the bottle is opened and the sterile seal is broken. If these preservatives lose their efficacy, the solution becomes more susceptible to microbial contamination.
Potential Dangers of Using Expired Drops
Using expired pink eye drops carries several risks, primarily due to reduced effectiveness and increased contamination. When active ingredients degrade, the medication may become useless for treating the infection, potentially prolonging symptoms or worsening the condition. This is especially concerning for antibiotic eye drops, as their decreased effectiveness could lead to inadequately treated infections and possibly contribute to antibiotic resistance.
Expired drops, particularly those that have been opened, can harbor harmful bacteria or fungi due to compromised sterility. Once the sterile seal is broken, germs can enter the bottle, and if preservatives are no longer functioning, these microorganisms can proliferate. Applying contaminated drops to the eye can introduce new or more severe infections, such as keratitis, an infection of the cornea that can lead to vision loss if left untreated.
Furthermore, the degradation of chemical compounds within the solution or the presence of new contaminants can cause irritation, inflammation, or adverse allergic reactions in the eye. This can manifest as burning, stinging, or increased redness, exacerbating the discomfort already present from pink eye.
Safe Practices for Eye Drop Use
Expired eye drops should always be discarded, regardless of whether the bottle has been opened or not. To dispose of them properly, you can mix the leftover medicine with an unwanted material like coffee grounds or kitty litter, then place the mixture in a sealable bag or container before putting it in the trash. Some pharmacies also offer take-back programs for safe medication disposal.
If you have pink eye or any other eye condition, consult a healthcare professional or pharmacist for a new, unexpired prescription or over-the-counter solution. It is not advisable to use a family member’s leftover eye drops, as this could lead to an infection.
Proper storage of eye drops helps maintain their stability and effectiveness until their expiration date. Most eye drops should be kept in a cool, dry place, away from direct sunlight and humidity, typically at room temperature between 15°C and 25°C. Some specific eye drops may require refrigeration, usually between 2°C and 8°C, so always check the package instructions.