A nurse is teaching a client how to draw up regular insulin and NPH insulin into the same syringe. Which of the following instructions should the nurse include?

A. Shake the NPH insulin until it is well mixed: NPH insulin should be gently rolled between the palms, not shaken vigorously, to avoid creating bubbles and affecting its potency. Gentle mixing ensures proper suspension without compromising the insulin. B. Draw up the NPH insulin into the syringe first: The correct technique is to draw up regular (clear) insulin first, followed by NPH (cloudy) insulin, to prevent contaminating the regular insulin with the longer-acting NPH. Drawing NPH first can alter the regular insulin’s action. C. Inject air into the regular insulin first: Injecting air into both insulin vials before drawing up doses equalizes pressure and facilitates accurate measurement. Air is injected first into the regular insulin vial to maintain proper technique when mixing insulins. D. Discard regular insulin that appears cloudy: Regular insulin is a clear solution. Cloudiness indicates contamination or expiration, so cloudy regular insulin should never be used. This instruction reinforces proper medication safety practices.