Insulin serves as a hormone in the body, enabling cells to absorb glucose from the bloodstream for energy. In individuals managing diabetes, manufactured insulin regulates blood sugar levels. Given its biological composition, insulin is sensitive to various conditions and has a defined shelf life, making adherence to its expiration dates important for effective diabetes management.
Diminished Efficacy
Insulin’s effectiveness diminishes over time due to the breakdown of its molecular structure. As a protein-based medication, insulin molecules can undergo degradation, where peptide chains break down, and aggregation, where molecules clump together. These structural changes reduce the insulin’s ability to lower blood glucose, making it less potent. This loss of potency is a progressive process.
Environmental factors influence the rate of insulin degradation. Exposure to extreme temperatures, both excessive heat and freezing, can accelerate this process. Temperatures outside the recommended range, typically between 36°F and 86°F (2.2°C to 30°C), can compromise insulin stability. Direct light and physical agitation also contribute to its deterioration. Visible signs like discoloration, cloudiness (for clear insulin), or the presence of clumps or crystals often indicate degraded insulin.
Risks to Health
The health consequence of using expired or degraded insulin is persistently high blood sugar, known as hyperglycemia. Since insulin loses its ability to effectively move glucose into cells, blood sugar levels remain elevated. This can lead to symptoms like increased thirst, frequent urination, fatigue, and blurred vision.
For individuals with Type 1 diabetes, using ineffective insulin carries a risk of developing diabetic ketoacidosis (DKA). DKA is a severe, potentially life-threatening complication occurring when the body, lacking sufficient insulin, breaks down fat for energy, producing acidic byproducts called ketones. Symptoms of DKA include nausea, vomiting, abdominal pain, rapid breathing, and a distinct fruity odor on the breath. While less common, degraded insulin might also cause localized skin reactions at the injection site, or rarely, pose a minor risk of infection if its sterility is compromised.
Immediate Actions to Take
If expired insulin has been used, check blood glucose levels immediately and more frequently. If blood sugar levels are elevated, administering a fresh, unexpired dose of insulin may be necessary, followed by monitoring glucose readings. Contact a healthcare provider promptly if blood sugar remains high or if symptoms of hyperglycemia, such as excessive thirst or fatigue, or signs of DKA, like nausea or rapid breathing, appear.
Proper disposal of expired insulin ensures safety and prevents accidental use. Expired insulin should not be discarded in regular household trash or flushed down the toilet. Many pharmacies, local hazardous waste facilities, or community take-back programs offer safe disposal options. Needles and syringes, or sharps, must be placed in designated sharps containers to prevent injuries. Consistently using unexpired and correctly stored insulin is key for effective diabetes management.