Proper administration and dosing of insulin is imperative to achieve maximum efficacy while avoiding hypoglycemia. Therefore, accuracy and precision of dose administration is crucial. There are two techniques for insulin administration in pets: by vial and syringe or insulin pen and pen needle. Both options are appropriate, but each comes with pros and cons. Insulin that is available as a pen includes Humulin-N, Novolin-N, Vetsulin, Lantus, Basaglar, Semglee, Toujeo, Levemir, and Degludec.
Insulin vials and syringes are a proven way to administer insulin in both humans and pets. Though the design of the insulin pen is newer, it has been shown to be equally effective for treatment. The AAHA endorses a “known propensity for up to 25% more insulin to be drawn up per dose especially for smaller insulin doses,” when referring to the use of an insulin syringe and needle for administration. Studies have also shown that even trained veterinarians and technicians displayed a >20% dose discrepancy when drawing a target dose of 1 IU in 50% of aspirates from a traditional vial-syringe insulin. This may lead to preference for insulin pens and their precision in the future.
After the first puncture, the insulin labeling indicates that it must be used within 30 to 80 days, with most requiring use within 56 days, depending on the specific product. This can potentially lead to product loss and waste due to large quantities inside the vials and the small dosing recommendations.
While both options have different advantages and disadvantages, the best option is one that suits the patient as well as the client. Whichever option is selected, thorough counseling should be completed with the client. If switching from a vial to a pen or vice versa, the differences should be highlighted and appropriately counseled on with the client given the different nature of administration between the two options.
- Behrend E, Holford A, Lathan P, et al. 2018 AAHA diabetes management guidelines for dogs and cats. J Am Anim Hosp Assoc 2018;54(1):p1-21
- Borin-Crivellenti, S., Bonagura, J. & Gilor, C. COMPARISON OF PRECISION AND ACCURACY OF U100 AND U40 INSULIN SYRINGES [Abstract]. JVIM 28, 1029 (2014).
- Sanyal D and Chowdhury A. Half insulin pen: an effective yet underutilized insulin delivery option. Current medical research and opinion. Mar 2021;37(5):p753-4. Doi: 10.1080/03007995.2021.1898356
- Thompson A, Lathan P, and Fleeman L. Update on insulin treatment for dogs and cats: insulin dosing pens and more. Vet Med. Apr 2015;6:129-42. Doi: 10.2147/VMRR.S39984
By Alexandria Gochenauer, PharmD, FSVHP