How to mix two insulins in one syringe
Other platforms explain it with text and video. In VMS you practice it on the patient.
Mixing regular and NPH insulin saves the patient a second injection. The order of the steps keeps the clear vial free of cloudy insulin, which would change every later dose.
What you need
- Regular insulin vial
- NPH insulin vial
- Insulin syringe in units
- Alcohol swabs
Step by step
Confirm the insulins can be mixed
Only certain pairs can be mixed, most often regular with NPH. Never mix long-acting insulins such as glargine or detemir with any other insulin. [1]
Check doses and total
Write down each dose and the total units. Have a second nurse check if policy requires it. [1]
Prepare the vials
Roll the NPH vial gently to mix it. Clean both rubber tops with alcohol and let them dry. [2]
Add air to NPH first
Inject air equal to the NPH dose into the NPH vial without touching the liquid. Remove the needle. [2]
Draw up regular insulin
Inject air equal to the regular dose into the regular vial, turn it upside down and draw the exact regular dose. Remove air bubbles. [2]
Draw up NPH
Insert the needle into the NPH vial and slowly draw until the syringe shows the total dose. If you draw too much, discard the syringe and start again. [2]
Give promptly
Recheck the total, give the injection under the skin and document both insulins and the site. [1]
Common errors
- Drawing cloudy NPH first and contaminating the regular vial.
- Mixing glargine with another insulin.
- Pushing extra insulin back into a vial after overdrawing.
Practice it in VMS
In VMS you do this on the patient, not on paper: every step goes on the checklist with a score, and in Teach mode Blocky tells you what comes next.
VMS cases that train this skill
Sources
- Open RN, Nursing Pharmacology 2e (CC BY 4.0)
- Open RN, Nursing Skills 2e (Chippewa Valley Technical College) (CC BY 4.0)
Steps adapted from Open RN, Nursing Pharmacology 2e and Open RN, Nursing Skills 2e (Chippewa Valley Technical College), licensed under CC BY 4.0. VMS is not affiliated with these organizations. Updated: 2026-10-11.