Insulin, a hormone produced by the pancreas, is a medication many people with diabetes rely on to manage their blood sugar levels. Maintaining stable blood sugar is important for overall health and preventing complications. While it might seem convenient to use insulin beyond its labeled date, it is generally not recommended or safe to use expired insulin. This is due to a potential loss of its intended effectiveness and an unpredictable action within the body.
Why Insulin Loses Potency
Insulin is a protein, and like all proteins, it can degrade over time. This degradation is influenced by factors such as temperature fluctuations, exposure to light, and air. When insulin degrades, its chemical structure changes, leading to a reduced ability to effectively lower blood sugar. This means that even if expired insulin looks normal, its active ingredients may no longer function as intended.
Manufacturers print an expiration date on insulin packaging to guarantee its potency and sterility up to that point. Beyond this date, the stability and effectiveness of the insulin cannot be assured. Opened insulin, or insulin in use, also has a shorter “use-by” date, even if the manufacturer’s expiration date has not yet passed.
Consequences of Using Expired Insulin
Using insulin that has lost its potency carries direct health implications. The primary risk is hyperglycemia, or high blood sugar, because the degraded insulin will not effectively reduce glucose levels in the bloodstream. Symptoms of hyperglycemia can include increased thirst, frequent urination, fatigue, and blurred vision. Prolonged or severe hyperglycemia can lead to serious complications.
One such severe complication is diabetic ketoacidosis (DKA). DKA is a life-threatening condition where the body, lacking sufficient insulin, starts breaking down fat for energy, producing harmful substances called ketones. Symptoms of DKA include nausea, deep breathing, and confusion, requiring immediate medical attention. The unpredictable nature of degraded insulin further complicates blood sugar management. Its action might be inconsistent, making it difficult to achieve stable glucose levels, which increases the risk of high blood sugar events.
Maximizing Insulin Shelf Life and Safe Disposal
Proper storage is important for maintaining insulin’s effectiveness until its expiration date. Unopened insulin should be stored in a refrigerator. It is important to never freeze insulin, as this can damage its structure and render it ineffective. Once opened or in use, insulin can typically be kept at room temperature for a specific period.
Insulin should always be protected from direct sunlight and extreme temperatures, such as those found in a hot car. Visual inspection before each use is important; do not use insulin if it appears discolored, cloudy, or contains clumps or solid particles.
For safe and responsible disposal of expired or unused insulin and related supplies, local guidelines should be followed. Needles, syringes, and lancets should be placed in a puncture-resistant sharps container. Expired insulin vials or pens can often be disposed of through medication take-back programs offered by pharmacies or local hazardous waste disposal centers.