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Insulin lispro

Brand names: Humalog, Admelog, Lyumjev

Insulin lispro is a rapid-acting insulin taken at mealtimes to control the rise in blood sugar after eating.

Brand namesHumalog, Admelog, Lyumjev
Type of medicineRapid-acting (mealtime) insulin
Prescription?Prescription
ImportantThis page is general information, not a prescription. Don't start, stop, or change a medicine without talking to your provider or pharmacist.

Overview

It starts working in about 15 minutes. It's usually used with a long-acting insulin, or in an insulin pump.

What it's used for

  • Type 1 diabetes
  • Type 2 diabetes

How to take it

  • Inject it within 15 minutes before a meal or right after eating, as your provider says.
  • Rotate injection spots.
  • Never share pens, even with a new needle.
  • Check your blood sugar as directed.

Your dose depends on your health and other medicines. Always follow your prescription label, and ask your pharmacist if anything is unclear.

Side effects

Common side effects

  • Low blood sugar
  • Weight gain
  • Redness or lumps where you inject
Call 911Severe low blood sugar: confusion, seizure, or passing out. Use glucagon if you have it, then call 911.
Call your provider todayFrequent low blood sugar or readings that stay high
Call your provider todayMuscle weakness or cramps (low potassium)

Warnings

  • Never inject it without eating soon after.
  • Know the signs of low blood sugar and keep fast sugar with you.

Other medicines, foods, and alcohol

  • Other diabetes medicines add to the risk of low blood sugar.
  • Beta blockers can hide signs of low blood sugar.
  • Alcohol can cause low blood sugar.

Tell your provider and pharmacist about every medicine, vitamin, and supplement you take.

Pregnancy and breastfeeding

Insulin is used in pregnancy. Work closely with your provider.

Missed doses, overdose, and storage

If you miss a dose

If you forget a mealtime dose, check your blood sugar and follow the plan your provider gave you. Don't take extra to catch up without guidance.

If someone takes too much

Call Poison Control at 1-800-222-1222 or get help online at poison.org. Call 911 if the person collapses, has a seizure, has trouble breathing, or can't be woken.

Storing it

Keep unopened pens and vials in the refrigerator (don't freeze). Once opened, follow the label for how long it lasts at room temperature. Keep away from heat and sunlight.

Conditions it's used for

Sources

Last updated 2026-11-13.