Generic name: insulin lispro [ IN-soo-lin-LISS-pro ]
Drug class: Insulin

Medically reviewed by Sanjai Sinha, MD. Last updated on May 6, 2024.

What is Humalog?

Humalog is a fast-acting insulin that starts to work about 15 minutes after injection, peaks in about 1 hour, and keeps working for 2 to 4 hours. Insulin is a hormone that works by lowering levels of glucose (sugar) in the blood.

Humalog is used to improve blood sugar control in adults and children with diabetes mellitus.

Humalog is used to treat type 2 diabetes in adults.

Humalog is also used to treat type 1 diabetes in adults and children who are at least 3 years old.

Warnings

Humalog is a fast-acting insulin that begins to work very quickly. If you use this medication with meal, use it within 15 minutes before or just after you eat.

Never share an injection pen, cartridge, or syringe with another person, even if the needle has been changed.

You should not use Humalog if you are having an episode of hypoglycemia (low blood sugar).

Humalog is only part of a complete program of treatment that may also include diet, exercise, weight control, foot care, eye care, dental care, and testing your blood sugar. Follow your diet, medication, and exercise routines very closely. Changing any of these factors can affect your blood sugar levels.

Humalog side effects

Get emergency medical help if you have signs of insulin allergy to Humalog: redness or swelling where an injection was given, itchy skin rash over the entire body, trouble breathing, fast heartbeats, feeling like you might pass out, or swelling in your tongue or throat.

Call your doctor at once if you have:

• weight gain, swelling in your hands or feet, feeling short of breath;

• low blood sugar - headache, hunger, sweating, irritability, dizziness, fast heart rate, and feeling anxious or shaky; or

• low potassium - leg cramps, constipation, irregular heartbeats, fluttering in your chest, increased thirst or urination, numbness or tingling, muscle weakness or limp feeling.

Common Humalog side effects may include:

• low blood sugar;

• weight gain;

• swelling in your hands or feet;

• itching; or

• thickening or hollowing of the skin where you injected the medicine.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Before taking this medicine

You should not use Humalog if you are allergic to insulin, or if you are having an episode of hypoglycemia (low blood sugar).

Humalog should not be given to a child younger than 3 years old. Humalog should not be used to treat type 2 diabetes in a child of any age.

To make sure Humalog is safe for you, tell your doctor if you have ever had:

• liver or kidney disease;

• heart problems; or

• low levels of potassium in your blood (hypokalemia).

Tell your doctor if you also take pioglitazone or rosiglitazone (sometimes contained in combinations with glimepiride or metformin). Taking certain oral diabetes medicines while you are using insulin may increase your risk of serious heart problems.

Tell your doctor if you are pregnant or breastfeeding.

Follow your doctor's instructions about using Humalog if you are pregnant or you become pregnant. Controlling diabetes is very important during pregnancy, and having high blood sugar may cause complications in both the mother and the baby.

How should I use Humalog?

Use Humalog exactly as it was prescribed for you. Follow all directions on your prescription label and read all medication guides or instruction sheets.

Humalog is injected under the skin using a syringe and needle, an injection pen, or with an infusion pump. A healthcare provider will teach you how to properly use this medicine by yourself.

Read and carefully follow any Instructions for Use provided with your medicine. Ask your doctor or pharmacist if you do not understand these instructions.

Prepare your injection only when you are ready to give it. Do not use if the medicine looks cloudy, has changed colors or has particles in it. Call your pharmacist for new medicine.

Humalog is to be used within 15 minutes before a meal, or right after eating.

Your healthcare provider will show you where on your body to inject insulin lispro. Use a different place each time you give an injection. Do not inject into the same place two times in a row. Do not inject into skin that is damaged, tender, bruised, pitted, thickened, scaly, or has a scar or hard lump.

Concentrated Humalog (200 units) must not be given with an insulin pump, or mixed with other insulins. Do not transfer insulin lispro from an injection pen to a syringe or a severe overdose could occur.

Never share an injection pen, cartridge, or syringe with another person, even if the needle has been changed. Sharing these devices can allow infections or disease to pass from one person to another.

You may have low blood sugar (hypoglycemia) and feel very hungry, dizzy, irritable, confused, anxious, or shaky. To quickly treat hypoglycemia, eat or drink a fast-acting source of sugar (fruit juice, hard candy, crackers, raisins, or non-diet soda).

Your doctor may prescribe a glucagon injection kit in case you have severe hypoglycemia. Be sure your family or close friends know how to give you this injection in an emergency.

Also watch for signs of high blood sugar (hyperglycemia) such as increased thirst or urination.

Blood sugar levels can be affected by stress, illness, surgery, exercise, alcohol use, or skipping meals. Ask your doctor before changing your dose or medication schedule.

Keep this medicine in its original container protected from heat and light. Do not freeze insulin or store it near the cooling element in a refrigerator. Throw away any insulin that has been frozen.

Storing unopened (not in use) insulin lispro:

• Refrigerate and use until expiration date; or

• Store at room temperature and use within 28 days.

Storing opened (in use) Humalog:

• Store the vial in a refrigerator or at room temperature and use within 28 days.

• Store the cartridge or injection pen (without a needle attached) at room temperature and use within 28 days.

Use a needle and syringe only once and place them in a puncture-proof "sharps" container. Follow state or local laws about how to dispose of this container. Keep it out of the reach of children and pets.

Related/similar drugs

Mounjaro, Ozempic, metformin, Trulicity, Lantus, Tresiba, Basaglar, Levemir, Novolog, sodium bicarbonate

What happens if I miss a dose?

Since Humalog is used before meals, you may not be on a timed dosing schedule. Whenever you use Humalog, be sure to eat a meal within 15 minutes. Do not use two doses at one time.

Keep insulin on hand at all times. Get your prescription refilled before you run out of medicine completely.

What happens if I overdose?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222. Insulin overdose can cause life-threatening hypoglycemia. Symptoms include drowsiness, confusion, blurred vision, numbness or tingling in your mouth, trouble speaking, muscle weakness, clumsy or jerky movements, seizure (convulsions), or loss of consciousness.

What should I avoid while using Humalog?

Insulin can cause low blood sugar. Avoid driving or operating machinery until you know how this medicine will affect you.

Avoid medication errors by always checking the medicine label before injecting your insulin.

Avoid drinking alcohol. It can cause low blood sugar and may interfere with your diabetes treatment.

What other drugs will affect Humalog?

Many other medicines can affect your blood sugar, and some medicines can increase or decrease the effects of insulin. Some drugs can also cause you to have fewer symptoms of hypoglycemia, making it harder to tell when your blood sugar is low. Tell each of your health care providers about all medicines you use now and any medicine you start or stop using. This includes prescription and over-the-counter medicines, vitamins, and herbal products.

Humalog Biosimilars

Biosimilar and interchangeable products are biological products that are highly similar to and have no clinically meaningful differences from the reference product.

Reference products

These are biological products that have already been approved by the FDA, against which biosimilar products are compared. There are 3 for Humalog.

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Further information

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use Humalog only for the indication prescribed.

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Medical Disclaimer

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