Samuel Grossman, BS Pharm, Pharm.D, CDE Answered 9/8/2015

Only certain kind of insulin products can be injected together specifically, NPH insulin and regular insulin and rapid acting insulin (epidra, humulog 100u/ml, and novolog). Insulin products, like Lantus for example, cannot be mixed with any other insulin in the same syringe because it requires specific acidity to work. Other insulin products like Levemir cannot be mixed with other insulin products in the same syringe as well. I would recommend for you to speak to your provider.There are ready-made available combination insulin products on the market that may make it easier for you and reduce the injection burden.