Lantus Solostar 100 IU/ml 5 x 3 ml is an injectable solution containing insulin glargine, which is designed to help control blood sugar levels in people with diabetes. The solution comes in pre-filled pens that deliver a single dose of 100 IU with each injection. It should be taken once a day, at the same time each day, to help keep blood sugar levels in the target range. It is typically used for type 1 and type 2 diabetes management in adults. This medication should be used as part of a overall diabetes management plan.