Tips to Improve Insulin Safety

Full update March 2022

The checklist below provides strategies and resources to help prevent insulin errors.


Suggested Approach

Safely prescribe/order insulin

  • Avoid writing orders with trailing zeros.13
    • correct: 10 units of regular insulin
    • incorrect: 10.0 units of regular insulin
  • Spell out the word “units” instead of abbreviating with “U” or “u.”13
  • Use TALLman lettering with look-alike drug names, such as HumuLIN and HumaLOG and NovoLIN and NovoLOG.6
  • Avoid writing “use as directed.”
  • Specify pens or vials on prescriptions to avoid confusion.16 For example, write the full name of the product to avoid confusion with pens, vials, or cartridges (e.g., Levemir FlexTouch).
  • Consider standardized ordering to reduce mistakes and avoid transcription errors.5
  • Use protocol-driven order sets that incorporate blood glucose monitoring and decision support for inpatients.1,7
  • Use our chart, How to Switch Insulin Products, (US subscribers; Canadian subscribers) for insulin conversion tips.

Prevent product mix-ups

  • Be aware of potential look-alike, sound-alike mix-ups, (e.g., lispro and Lantus), when ordering and dispensing insulin.
  • Put safeguards in place such as storing products in separate locations or using shelf tags to avoid mix-ups when dispensing similar looking pens or vials, or for different strengths of insulin (e.g., U-100, U-200, U-300, U-500).
  • Educate patients and prescribers about the differences between the different products as related to onset, duration of action, and intended use. See our charts, Comparison of Insulins, (US subscribers; Canadian subscribers) for specifics.
  • Avoid attaching labels to the cap of a pen. If caps are interchangeable between pens, this could lead to mix-ups.
  • Encourage patients who use multiple types of insulin to double-check that they are using the right pen or vial prior to administration of every dose.
  • For inpatients, use standard concentrations of insulin infusions prepared in the pharmacy.1
  • Ensure that pharmacy technicians are knowledgeable about insulin and potential for serious consequences with errors with our technician tutorials:

Be aware of factors that can impact blood glucose.

  • Watch for meds that might impact blood glucose (e.g., corticosteroids, quinolones).
  • If patients are receiving multiple med drips containing dextrose, be mindful of the total dextrose content.
  • Recommend blood glucose monitoring to prevent hypoglycemia or hyperglycemia when blood glucose might be affected by meds (i.e., starts, stops, dose changes), illness, changes in nutrition, etc.4
  • For inpatients, use:
    • evidence-based protocols/order sets for glucose monitoring during planned and unplanned interruptions in nutrition.1
    • a “hypoglycemic team” to develop a standardized approach to preventing and detecting hypoglycemia.

Understand special considerations with U-500 insulin

  • U-500 is FIVE times as concentrated as U-100 insulins, containing 500 units/mL, instead of 100 units/mL. But it’s NOT just a more concentrated form of regular insulin. Its onset (within 30 minutes) is similar to U-100 insulin and its duration (12 to 24 hours) is similar to NPH insulin.14,15
  • Recommend subcutaneous dosing only. U-500 should not be administered intravenously (IV) or intramuscularly (IM).14,15
  • To prevent mix-ups, include the word “concentrated” on orders for U-500 insulin. For example, “insulin human regular (CONCENTRATED) U-500, 150 units (0.3 mL), inject subcutaneously three times daily before meals.”
  • U-500 KwikPens (U-500 Humulin R KwikPen [US]; Entuzity KwikPen [Canada]) available as 3 mL (1,500 units)/pen measure doses in ACTUAL insulin units (doses range from 5 to 300 units/injection using 5 unit increments).14,15
    • Recommend using the dose window, not counting clicks, to draw up an accurate dose.8,14,15
        • The dose indicator should line up with the total dose being drawn up.
        • Even numbers are printed on the dial (e.g., 10, 20); odd numbers (e.g., 15, 25) are the line in between each number pair.
    • Prime U-500 KwikPens with 5 units of insulin instead of the typical 2 units with other pens.8,15
      • Pens may need to be primed multiple times to remove all of the bubbles.8,15
      • If insulin cannot be seen at the end of the needle after EIGHT tries, replace the needle and prime the new needle.8,15
    • Ensure dexterity issues aren’t a concern, especially with larger doses. The dose button extends as the dose increases.
      • Counsel patients or caregivers to ensure understanding of dosing and administration.
  • U-500 insulin vials (20 mL [10,000 units]/vial [US only]): Ensure patients are prescribed and use U-500 insulin syringes (calibrated to U-500 insulin with 5-unit increment markings to a maximum of 250 units/syringe) to safely draw up doses.
    • Errors can occur with U-100 insulin syringes or tuberculin syringes.2 If U-500 syringes are not available follow these tips to reduce the risk of confusion and error:17,18
      • When possible, give preference to tuberculin syringes over U-100 syringes and include the units AND mLs to be injected. Example sig: inject 200 units (0.4 mL) twice daily 30 minutes before breakfast and dinner.
      • If U-100 insulin syringes must be used, include the units AND the unit marking to be injected. Example sig:
        inject 200 units (40 unit marking) twice daily 30 minutes before breakfast and dinner.18
      • When possible, avoid switching types of syringes. If switching is necessary, consider marking the amount the patient needs to inject on the syringe.
    • In the hospital, draw up U-500 doses in the pharmacy. Or, consider using one U-500 pen per patient.1

Accurate dosing by patients

  • For patients with poor vision and/or dexterity, consider:
    • tools such as syringe magnifiers or a device that indicates the correct dose has been drawn up (e.g., Count-a-dose).
    • the use of insulin pens instead of vials.
  • Improperly mixing suspensions (e.g., Humulin N, Humalog Mix 75/25 [US], Novolin N [US], Novolin ge NPH [Canada]) can lead to over-dosing or under-dosing.
    • Vials: educate patients to roll (not shake) gently at least ten times before use.9
    • Pens: educate patients to roll and tip up and down gently at least ten times each before use.
  • Note: not all types of insulin can be mixed in the same syringe. Check product labeling before mixing.
  • Advise patients to routinely:
    • check expiration dates
    • visually inspect insulin to be sure it’s clear (for solutions) or uniformly cloudy (for suspensions), without clumps/particles.

Safe use of insulin pens

  • Label insulin pens (not just bags) dispensed to patient-care units for individual patients.1
  • Consider adding tamper-evident seals on pens to identify which ones have been used.
  • Use the motto, “one pen, one patient.”1,10 Pens should only be used for a single patient, even if the needle is changed.10,11
  • Discourage “work-arounds” such as withdrawing doses for multiple patients from a single pen cartridge.
  • Advise patients who use more than one pen to double-check that they have the correct pen before administering a dose.
  • Review information such as priming and operation of the pen with patients, caregivers, etc. Include steps such as:
    • attach the needle
    • prime the pen before each dose to expel air bubbles
    • dial the dose
    • press the button completely and leave the needle in the skin for 5 to 10 seconds to deliver the full dose
    • discard the needle
  • Train patients/caregivers on proper use. If available, give printed step-by-step instructions (specific to US products):
  • Educate patients not to reuse needles with their pens. Reuse can dull needles and lead to pain. Reuse can also lead to infection.
  • Discourage leaving needles on the pen due to increased risk of air bubbles, leaks, or clogging.12
  • Prescribe insulin quantities in multiples of mLs or units per box of pens, based on how supplied (e.g., 1500 units [15 mL] if there are three U-100 5 mL pens per box). Be sure that the quantity prescribed matches the intended days’ supply.
  • Include an Rx for pen needles with prescriptions for pens.

Time insulin doses properly

  • Make sure that appropriate and specific times are indicated on orders for insulin. Avoid dosing schedules such as “bid.”
  • Use our algorithms, Initiation and Adjustment of Insulin Regimens for Type 2 Diabetes (US subscribers; Canadian subscribers).
  • Use insulin infusion protocols in critical patients.4
  • Recommend rapid-acting insulin administration with the first bite of a meal.1
  • Consider administering prandial insulin at the end of the meal in patients with variable food intake.1

Educate about insulin use

  • Educate patients about insulin use.
    • Review proper injection technique (e.g., skin prep, angle of needle insertion, pinching a skinfold, site rotation).9
    • Observe the patient administer a dose, with his or her own supplies, to identify errors and improve technique.
  • Consider referring patients to a diabetes education program or certified diabetes educator (CDE) including at hospital discharge.4 Use the following websites to find a local CDE:
  • Educate patients about the signs and symptoms of hypoglycemia, and its management.
    • In the US, use CPT code 99211 to bill for insulin teaching provided by a nurse or pharmacist on a separate visit.3
  • Participate in education and teaching of other health care professionals who are involved in the use of insulin (e.g., prescribing, compounding, dispensing, administering, monitoring).1

Store insulin properly

  • Avoid storing U-500 insulin in patient care areas.1
  • Label insulin vials and pens with proper storage instructions, including when to refrigerate products and beyond-use dating when products are stored at room temp, if applicable. For specifics use our:
  • Remind patients when devices should NOT be stored in the refrigerator, such as in-use insulin pens.
  • Store U-500 insulin and U-500 syringes separate from other insulin or syringes to avoid mixups.


  1. Cobaugh DJ, Maynard G, Cooper L, et al. Enhancing insulin-use safety in hospitals: Practical recommendations from an ASHP Foundation expert consensus panel. Am J Health Syst Pharm. 2013 Aug 15;70(16):1404-13.
  2. U-500 insulin errors. (Accessed February 17, 2022).
  3. Association of Diabetes Care and Education Specialists. Diabetes coding table. 2021. (Accessed February 17, 2022).
  4. American Diabetes Association Professional Practice Committee; American Diabetes Association Professional Practice Committee, Draznin B, et al. 16. Diabetes Care in the Hospital: Standards of Medical Care in Diabetes-2022. Diabetes Care. 2022 Jan 1;45(Supplement_1):S244-S253.
  5. ISMP. High-alert medications in acute-care settings. August 23, 2018. (Accessed February 17, 2022).
  6. ISMP. Look-alike drug names with recommended tall man letters. November 20, 2016. (Accessed February 17, 2022).
  7. ISMP Canada. Knowledge translation of insulin use interventions/safeguards. (Accessed February 17, 2022).
  8. Instructions for use: Entuzity KwikPen. Updated August 17, 2020. (Accessed February 17, 2022).
  9. Saltiel-Berzin R, Cypress M, Gibney M. Translating the research in insulin injection technique: implications for practice. Diabetes Educ. 2012 Sep-Oct;38(5):635-43.
  10. ISMP Canada. Alert: use of one insulin pen for multiple patients is a high-risk practice. May 22, 2013. (Accessed February 17, 2022).
  11. CDC clinical reminder: insulin pens must never be used for more than one person. (Accessed February 17, 2022).
  12. Insulin pen safety. (Accessed February 17, 2022).
  13. ISMP. List of error-prone abbreviations. February 5, 2021. (Accessed February 17, 2022).
  14. Product monograph for Entuzity KwikPen. Eli Lilly Canada. Toronto, ON M5X 1B1. March 2021.
  15. Product information for Humulin R U-500. Lilly USA. Indianapolis, IN 46285. November 2019.
  16. Shubrook JH, Becerra NM, Adkins SE, Guo A. Insulin: a 2014 primer, part 2 insulin delivery and insulin pumps. Primary Care Reports. 2014;20:101-10.
  17. Samaan KH, Dahlke M, Stover J. Addressing safety concerns about U-500 insulin in a hospital setting. Am J Health Syst Pharm. 2011 Jan 1;68(1):63-8.
  18. ISMP. As U-500 insulin safety concerns mount, it’s time to rethink safe use of strengths above U-100. October 31, 2013. (Accessed February 17, 2022).

Cite this document as follows: Clinical Resource, Tips to Improve Insulin Safety. Pharmacist’s Letter/Prescriber’s Letter. March 2022. [380308]