Insulin lispro, which was first approved for use in 1996, is a type of insulin used to treat type 1 and type 2 diabetes. This medication is used by injection under the skin or within an insulin pump, not to mention that it is typically taken around the time of eating. Insulin lispro basically works the same as human insulin by increasing the amount of glucose that tissues take in and decreasing the amount of glucose made by the liver. Bear in mind that this brand of insulin is two times stronger than other brands. Therefore, you need to be extra careful when you measure a dose. In fact, accidental overdose may lead to very bad side effects or life-threatening low blood sugar. And if you are 65 or older, use this medicine (insulin lispro pens) with care, considering you could have more side effects. It is worth noting that using Insulin lispro during pregnancy and breastfeeding is generally safe. You should, however, tell your doctor if you are pregnant, plan on getting pregnant, or are breast-feeding, because after all, you will need to talk about the benefits and risks to you and the baby.