Insulin types, storage, mixing, injection technique, and site rotation
Insulin management is one of the highest-stakes clinical responsibilities in home health nursing. Insulin errors — wrong type, wrong dose, wrong technique, improper storage — can cause severe hypoglycemia or prolonged hyperglycemia. This lesson reviews the pharmacology, safety practices, and teaching points that define competent insulin management in the home setting.
Understanding insulin pharmacokinetics — onset, peak, and duration — is essential for timing administration, anticipating hypoglycemia risk, and educating clients.
Lispro (Humalog), aspart (NovoLog), glulisine (Apidra): onset 10–30 minutes, peak 1–2 hours, duration 3–5 hours. Given immediately before or with a meal. If a client takes rapid-acting insulin and then does not eat, hypoglycemia risk is high — never administer without confirming the client will eat.
Humulin R, Novolin R: onset 30–60 minutes, peak 2–4 hours, duration 6–8 hours. Given 30 minutes before meals. Also used in insulin infusion pumps and sliding scale regimens.
Humulin N, Novolin N: onset 1–2 hours, peak 4–12 hours, duration 12–18 hours. Must be gently rolled (not shaken) before drawing. White, cloudy appearance is normal.
Glargine (Lantus, Basaglar), detemir (Levemir), degludec (Tresiba): essentially peakless with 20–42 hour duration. Given once or twice daily at consistent times. Glargine cannot be mixed with other insulins.
Unopened insulin should be refrigerated (36–46°F) until needed. The current-use vial or pen may be kept at room temperature — below 77°F for most products, up to 86°F for some — for 28–30 days. Beyond that, potency degrades. Never freeze insulin — freezing denatures the protein. Discard any insulin that has been frozen, exposed to excessive heat, appears clumped or cloudy when it should be clear, or has changed color.
Subcutaneous injection sites in order of absorption speed: abdomen (fastest) > arm > thigh > buttock (slowest). Rotate sites within each region 2–3 cm apart and rotate between regions to prevent lipohypertrophy — areas of hard, fatty tissue caused by repeated injections at the same spot. Lipohypertrophy visibly alters skin texture and dramatically impairs insulin absorption, causing unpredictable glucose levels. Assess all injection sites at every visit and teach clients to feel for lumps.
Inject at 90° into a skin fold in most adults. Needle length selection: 4–6mm needles are appropriate for most adults — longer needles risk intramuscular injection, which speeds absorption unpredictably.
Insulin pens are never shared between clients — even with a needle change, pen cartridges may allow backflow of blood that could transmit bloodborne pathogens. Attach a new needle for each injection. After the injection, keep the needle in for 5–10 seconds before removing to ensure complete dose delivery. Perform a 2-unit air shot before each injection to confirm pen function and expel air.
Complete this 5-question quiz with 80% or higher to earn your CEU credit for this lesson.