Insulin Administration and Safety

Insulin is a polypeptide hormone that facilitates glucose uptake by cells. It is the primary treatment for Type 1 diabetes and is used in many Type 2 diabetes patients. In the hospital setting, insulin is used to manage hyperglycemia, treat DKA, and protect cells in hyperkalemia.

Insulin is given subcutaneously (SQ). Approved injection sites are:

Site rotation is essential to prevent lipohypertrophy — a build-up of fatty tissue at repeatedly injected sites. Lipohypertrophy impairs insulin absorption, causing erratic glucose control.

• Within-site rotation: Move injection at least 1 cm (about a finger width) from the previous site within the same anatomical area
• Between-site consistency: Use the same body region (e.g., abdomen) for the same type of insulin to maintain consistent absorption
• Inspect sites: Palpate and visually inspect for lipohypertrophy (firm, rubbery areas), lipodystrophy, bruising, or inflammation. Avoid injecting into affected areas.
• Documentation: Record injection site used at each administration to support systematic rotation

1. Wash hands and prepare insulin per facility protocol (double-check performed)
2. Select and cleanse the injection site with alcohol; allow to fully dry
3. If using NPH or premixed insulin: gently roll (do not shake) the vial to resuspend
4. Pinch up subcutaneous tissue (especially for thin patients)
5. Insert needle at 45–90 degree angle depending on patient body habitus and needle length
6. Inject insulin at a slow, steady rate; do not aspirate
7. Hold for 5–10 seconds (pen injectors) before withdrawing to prevent leakage
8. Withdraw needle and apply gentle pressure — do not rub (rubbing increases absorption rate unpredictably)
9. Dispose of needle immediately in sharps container — never recap
10. Check blood glucose post-administration per orders; document site, dose, time, and glucose

Hypoglycemia (blood glucose < 70 mg/dL) is the most dangerous acute complication of insulin therapy. Severe hypoglycemia (< 54 mg/dL) can cause seizure, loss of consciousness, and death.

• Inspect insulin before each use — discard if cloudy (except NPH, which is normally cloudy), discolored, or has particles (except NPH suspension)
• Do not use expired insulin
• Glargine (Lantus) cannot be mixed with other insulins — precipitates and changes absorption profile

• Independent double-check: Two nurses independently verify insulin type, dose, patient identity, blood glucose, and concentration before administration
• Concentration verification: Confirm U-100 vs U-500. Use U-100 insulin syringes for U-100 only. U-500 requires special syringes or dosing guidance from pharmacy.
• Only Regular insulin goes IV: All other insulins are for subcutaneous use only. Administering NPH, glargine, or rapid-acting insulin IV is a medication error.
• IV insulin infusion: Requires weight-based protocol, dedicated infusion pump, hourly glucose checks, and frequent electrolyte monitoring (especially K⁺)
• Pen sharing is never allowed: Insulin pens are for one patient only — needle changes do not prevent bloodborne pathogen transmission from the pen reservoir
• Read the order carefully: "Units" written as "U" can be mistaken for "0" — always spell out "units." ISMP Do-Not-Use abbreviation.
• Check meal delivery: Prandial insulin is given when the meal tray arrives and is confirmed to be eaten. Not before delivery.

• Know your insulins: Name, type, dose, and timing. Carry a list. Know which is basal (long-acting) and which is mealtime (rapid/short-acting).
• Hypoglycemia kit: Always carry fast-acting glucose source. Know the 15-15 rule. Wear medical alert identification.
• Check blood glucose before meals and at bedtime as ordered; more frequently when sick or exercising
• Sick day rules: Do not stop insulin when sick — illness increases insulin resistance. Adjust dose per sick day plan and contact provider.
• Site care: Rotate sites systematically. Report any hard, rubbery areas to the healthcare provider.
• Sharps disposal: Use a sharps container. Do not recap needles. Contact local pharmacy or health department for disposal options.

• Only Regular insulin can be given IV. Rapid-acting, NPH, and long-acting insulins are subcutaneous only.
• Check BG before insulin. Never give prandial insulin if the meal is not in front of the patient.
• Glargine (long-acting) has no peak — relatively flat profile. Cannot be mixed with any other insulin.
• NPH is the only cloudy insulin — all others should be clear. Roll NPH gently to resuspend.
• Hypoglycemia treatment priority: if patient is alert — 15 g carbs orally. If unconscious — D50W IV or glucagon IM.
• U written as "U" is on the ISMP Do-Not-Use list — it looks like "0" and can lead to tenfold overdose. Always write "units."
• Lipohypertrophy causes unpredictable insulin absorption — prevent by rotating sites
• In DKA: IV Regular insulin infusion — hold until K⁺ ≥ 3.5 mEq/L. Insulin drives K⁺ into cells → worsens hypokalemia.