Insulin prescribing

Prescribing enough insulin

Recently the diabetes service has seen several patients who are not receiving enough insulin to last them for 3 months.

Patients are advised to prime their pens with at least 2 units of insulin before every injection. This is to ensure they receive accurate doses of insulin by removing any air inside the cartridge, and also to check that the cartridge is intact, and not cracked. If the cartridge is cracked, insulin will leak out of the side of the cartridge instead of coming out of the needle; there have been cases of diabetic ketoacidosis from patients using cracked cartridges.

If 2 units are used for priming each injection, this can add up to between 1-3 additional 3mL cartridges in 3 months. Please make sure you calculate enough insulin to allow for priming with each injection.


Pre-mixed insulins

It is important that patients inject pre-mixed insulin before dinner. Please make sure when you prescribe that the instructions read ‘BEFORE DINNER’ rather than selecting ‘nocte’ which could be labelled as ‘BEDTIME’ when dispensing.


Pen storage

Please discuss correct storage of pens with patients so they know pre-loaded pens that are in use are not kept in the fridge. Spare pens can be kept in the fridge but once they are in use, and have a needle attached, they should be kept out of the fridge. If they remain in the fridge, insulin can leak out and pens that are frequently moved in and out of the fridge can accumulate air bubbles.


Please contact Rab Burtun, Diabetes Clinical Nurse Specialist, Waitemata DHB for more information.

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