How to Switch From Levemir to Lantus

Lantus and Levemir are both types of long-acting insulin known as basal insulin; diabetics on insulin injection therapy typically administer a dose of basal insulin twice daily to provide a small, continuous amount of insulin to the body throughout the day and night. Lantus is composed of dissolved glargine (a synthetic derivative of human insulin), while Levemir contains dissolved detemir. While they both provide long-acting (12 to 24 hour) insulin, they deliver insulin throughout the bloodstream in different ways. Switching between the two for cost or effectiveness purposes is not difficult, but requires extra monitoring and may require adjusting your current insulin regimen.

Make an appointment with your doctor to discuss your desire to switch to Lantus. In most states, you will need a new prescription from your doctor to switch from Levemir to Lantus; it is not the same as simply switching from a formulary to a generic drug, or just switching between different manufacturers.

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Inject the same number of units of Lantus at the same time periods as you were injecting Levemir. The two insulins have a 1:1 ratio.

Monitor your blood glucose closely between the 12 and 24 hours after your initial Lantus injection, and discuss any changes with your doctor. Technically, it is suggested that Levemir be administered twice a day but Lantus only be administered once daily; however, many healthcare professionals, like Dr. Richard Bernstein, believe that both should be injected every 12 hours for optimal control. It takes two hours for either Levemir or Lantus to begin working, and each lasts for 18 to 24 hours in the bloodsteam.

This can mean you run higher between hours 18 and 24 on a once-daily injection regimen; since different bodies reach to Levemir and Lantus in slightly different ways, it’s important to notice where your blood sugar levels are going toward the end of this time period. Some people may discover that Lantus lasts a full 24 hours in their system, so they can reduce their basal injections to once per day.


Never switch insulin without consulting your doctor first.

If your body responds more readily to Lantus than to Levemir, you may experience some episodes of hypoglycemia (low blood sugar). Careful monitoring and a ready supply of fast-acting sugar, such as juice or raisins, can help to avoid or treat lows; discuss any unusual hypoglycemic events with your doctor, as you may need to lower your basal insulin dosage.