Insulin mixing combines two different types of insulin into a single syringe before injection. This technique allows for specific blood sugar control by leveraging the distinct action profiles of different insulins, such as rapid-acting and intermediate-acting types. The main benefit is reducing the total number of daily injections, streamlining the insulin regimen. This process requires precision to ensure correct dosage and maintain the efficacy of both insulin types.
Essential Supplies and Preparation
Before mixing insulin, gather all necessary supplies. You will need two insulin vials—typically one clear, fast-acting (like Regular) and one cloudy, intermediate-acting (like NPH)—along with an appropriate insulin syringe and alcohol swabs. Syringe sizes commonly include 0.3 mL for doses under 30 units, 0.5 mL for 30-50 units, and 1.0 mL for doses over 50 units.
Wash your hands thoroughly with soap and water to minimize contamination. Carefully check both insulin vials for appearance, expiration dates, and type. Clear insulin should be transparent; NPH insulin is naturally cloudy. Do not use clear insulin if it appears cloudy, discolored, or contains particles. For cloudy insulin, gently roll the vial between your palms 10-20 times until uniformly mixed, avoiding vigorous shaking that creates air bubbles. Clean the rubber stoppers of both vials with separate alcohol swabs and allow them to air dry completely.
Step-by-Step Mixing Procedure
Insulin mixing requires drawing both types into a single syringe in a specific order: “clear before cloudy.” This sequence prevents contamination of the clear, fast-acting insulin vial with the longer-acting, cloudy insulin, ensuring each type maintains its effectiveness.
First, draw air into the syringe equal to your cloudy insulin dose. Insert the needle into the cloudy insulin vial, inject the air, and remove the syringe without drawing insulin. Next, draw air into the syringe equal to your clear insulin dose. Insert the needle into the clear insulin vial, inject the air, then invert the vial and syringe. With the needle tip submerged, draw the prescribed clear insulin dose into the syringe.
After withdrawing the clear insulin, remove the syringe from the clear vial. Insert the needle into the cloudy insulin vial that received air. Invert the cloudy vial and syringe, ensuring the needle tip is submerged. Slowly pull the plunger to draw the prescribed cloudy insulin dose, adding it to the clear insulin already in the syringe. Avoid pushing any clear insulin back into the cloudy vial, as this can affect its action.
Once both insulins are drawn, check the syringe for large air bubbles. If present, gently tap the syringe to dislodge them, then carefully push the plunger to expel the air without losing insulin. Administer the mixed insulin immediately, ideally within 5-15 minutes, as rapid-acting insulin can begin to bind with NPH, potentially altering its action.
Safe Handling and Disposal
After administering mixed insulin, proper handling and disposal of the used syringe are crucial for safety. Immediately after injection, do not recap, bend, or break the used needle. Place the entire syringe directly into a designated sharps container.
Sharps containers are puncture-resistant plastic containers with tight-fitting, screw-on lids, such as a heavy-duty laundry detergent bottle or a commercially available sharps container. Avoid glass, clear plastic, or coffee cans, as they may not provide adequate protection. Label the container “Contains Sharps” and keep it out of reach of children and pets. Once the container is about three-quarters full, or reaches its fill line, seal the lid tightly with heavy-duty tape and prepare for disposal according to local regulations. Disposal methods vary by region, including community sharps disposal programs, mail-back services, or specific household trash guidelines.
For insulin storage, keep unopened vials refrigerated between 36°F and 46°F (2°C and 8°C) until their expiration date, away from the freezer. Once opened, most insulin vials can be stored at room temperature, typically 59°F to 86°F (15°C to 30°C), for up to 28 days. Avoid exposing insulin to direct heat, strong light, or freezing temperatures, as these conditions compromise its effectiveness.