Administering insulin correctly directly impacts blood glucose control for individuals with diabetes. When combining different types of insulin in a single injection, mastering the proper technique is important. Accurate preparation ensures the medication works as intended, contributing to overall health.
Understanding Insulin Types and the “Clear to Cloudy” Rule
Insulin comes in various forms, each designed to act differently within the body. Clear insulin refers to rapid-acting or short-acting solutions, such as regular insulin (e.g., Humulin R, Novolin R), which begin to work quickly to manage blood sugar spikes after meals. These insulins are clear because they are pure solutions without added substances that would alter their appearance.
Cloudy insulin denotes intermediate-acting insulins like NPH (Neutral Protamine Hagedorn) insulin (e.g., Humulin N, Novolin N). This type appears cloudy due to the presence of protamine, a protein added to slow down its absorption and prolong its effect in the body. The “clear to cloudy” rule dictates that when mixing clear and cloudy insulins in the same syringe, the clear insulin must always be drawn into the syringe first, followed by the cloudy insulin. This order prevents the cloudy NPH insulin from contaminating the clear, fast-acting insulin vial. Even a minuscule amount of NPH introduced into a clear insulin vial could alter its rapid action, reducing effectiveness and impacting blood sugar control.
Step-by-Step Guide to Drawing Up Insulin
Begin by gathering all necessary supplies: an insulin syringe, alcohol swabs, and both the clear and cloudy insulin vials. Wash your hands thoroughly with soap and warm water for at least 20 seconds to prevent contamination.
Prepare the cloudy insulin by gently rolling the vial between your palms until the solution appears uniformly milky white. This ensures the suspended particles are evenly distributed, as cloudy insulin naturally settles. Avoid vigorous shaking, which can create air bubbles that may lead to an inaccurate dose.
Use a fresh alcohol swab to clean the rubber stoppers of both the clear and cloudy insulin vials. Swab each stopper and allow them to air dry completely.
Inject air into the cloudy (NPH) insulin vial, matching the amount of cloudy insulin units you plan to withdraw. Remove the syringe from the cloudy vial without drawing any insulin. This step helps equalize the pressure inside the vial.
Inject air into the clear (regular) insulin vial, matching the amount of clear insulin units you intend to withdraw. Without removing the needle, invert the clear insulin vial and carefully draw out the prescribed dose of clear insulin. Inspect the syringe for any large air bubbles; if present, gently flick the syringe to move them to the top and push the plunger to expel them back into the vial.
Insert the needle into the cloudy (NPH) insulin vial, being careful not to push any clear insulin already in the syringe into the cloudy vial. Invert the cloudy vial and slowly draw the desired amount of cloudy insulin into the syringe, until the total dosage is reached. Administer the mixture within 5 to 15 minutes, as the regular insulin can bind to NPH, which may reduce its quick action over time.
Important Safety Considerations
Inspect your insulin vials for expiration dates and any changes in appearance before each use. Insulin that is normally clear should not appear cloudy, and any insulin with clumps, discoloration, or solid particles should be discarded immediately. These visual cues indicate the insulin has spoiled and may no longer be effective.
Proper storage of insulin is important for maintaining its potency. Unopened insulin vials should be kept refrigerated at temperatures between 36°F and 46°F (2°C and 8°C) until their expiration date. Once opened, most insulin vials can be stored at room temperature, between 59°F and 86°F (15°C and 30°C), for up to 28 days. Insulin should never be frozen or exposed to direct heat or sunlight, as extreme temperatures can degrade the medication.
Used syringes and needles are sharps and require careful disposal to prevent accidental needlestick injuries and the spread of infection. Never throw loose needles or syringes into regular trash or recycling bins. Place them immediately into a puncture-resistant container, such as a designated sharps disposal container or a heavy-duty plastic laundry detergent bottle.
This container should be clearly labeled and kept out of reach of children and pets. When the container is about three-quarters full, seal it securely and follow local guidelines for proper disposal, which may include community collection sites or mail-back programs.
Do not reuse needles or share syringes, as this poses a significant health risk. If you have any uncertainties about your insulin dosage, mixing procedure, or storage, consult a healthcare professional or pharmacist for personalized guidance.