Medication Search: Humalog

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Common Name:

insulin lispro


How does this medication work? What will it do for me?

Insulin is a naturally occurring hormone made by the pancreas that helps the body use or store the glucose (sugar) it gets from food. For people with diabetes, either the pancreas does not make enough insulin to meet the body’s requirements, or the body cannot properly use the insulin that is made. As a result, glucose cannot be used or stored properly and accumulates in the bloodstream. Insulin injected under the skin helps to lower blood glucose levels.

There are many different types of insulin and they are absorbed at different rates and work for varying periods of time. Insulin lispro is a rapid-acting insulin. It takes about 10 to 15 minutes after injection to begin working and has its maximum effect between 45 minutes and 150 minutes. It stops working after 3.5 to 5 hours.

This medication may be available under multiple brand names and/or in several different forms. Any specific brand name of this medication may not be available in all of the forms or approved for all of the conditions discussed here. As well, some forms of this medication may not be used for all of the conditions discussed here.

Your doctor may have suggested this medication for conditions other than those listed in these drug information articles. If you have not discussed this with your doctor or are not sure why you are being given this medication, speak to your doctor. Do not stop using this medication without consulting your doctor.

Do not give this medication to anyone else, even if they have the same symptoms as you do. It can be harmful for people to use this medication if their doctor has not prescribed it.

What form(s) does this medication come in?


Each 10 mL vial contains 100 units of human insulin analogue (insulin lispro) for every 1 mL. Nonmedicinal ingredients: glycerol, dibasic sodium phosphate, m-Cresol, zinc, water for injection, and hydrochloric acid or sodium hydroxide to adjust for pH.

Humalog® KwikPen™/Cartridge

100 units/mL
Every 1 mL contains 100 units of human insulin analogue (insulin lispro). Nonmedicinal ingredients: glycerol, dibasic sodium phosphate, m-Cresol, zinc, water for injection, and hydrochloric acid or sodium hydroxide to adjust for pH.

200 units/mL
Every 1 mL contains 200 units of human insulin analogue (insulin lispro). Nonmedicinal ingredients: glycerol, tromethamine, m-cresol, zinc oxide, hydrochloric acid, sodium hydroxide (for pH adjustment), and water for injection.

How should I use this medication?

Your required dose of insulin depends on how much natural insulin your pancreas is producing and how well your body is able to use the insulin. Your doctor or diabetes educator will determine the appropriate dose for you according to various lifestyle factors and the blood glucose values obtained while monitoring your blood glucose.

Your dose of insulin should be injected subcutaneously (under the skin), exactly as instructed by your doctor or diabetes educator. The dose of insulin is measured in international units (IU). Insulin lispro is injected under the skin within 15 minutes before the start of a meal. If necessary, insulin lispro may be given within 20 minutes after starting the meal. Injecting the insulin earlier or later than this window of time may cause low blood glucose levels.

Insulin lispro should be clear and colourless. Do not use the insulin if you notice anything unusual in the appearance of the solution, such as cloudiness, discoloration, or clumping.

There are two strengths of insulin lispro: 100 unit/mL and 200 unit/mL. Use only the strength of insulin that has been recommended to you by your doctor or diabetes educator. It is also important when you are using an insulin pen that you use the correct pen device for the strength of insulin you are using. The 200 unit/mL concentration should not be mixed with any other insulins, nor should it be used in insulin infusion pumps.

Many things can affect the dose of medication that a person needs, such as body weight, other medical conditions, and other medications. Do not change the way that you are using the medication without consulting your doctor.

It is very important that you use this medication exactly as prescribed by your doctor. The timing of insulin with respect to your meals is crucial to keeping blood glucose under control and preventing unwanted side effects.

Keep unopened bottles of insulin in the refrigerator until needed; they may be used until the expiry date on the label. Never allow insulin to freeze. Insulin that is currently in use may be kept at room temperature for 28 days only and then discarded. Do not expose insulin to extremely hot temperatures or to sunlight. Keep insulin out of the reach of children.

Do not dispose of medications in wastewater (e.g. down the sink or in the toilet) or in household garbage. Ask your pharmacist how to dispose of medications that are no longer needed or have expired.

Who should NOT take this medication?

Do not use insulin lispro if you:

  • are allergic to insulin or any ingredients of the medication
  • have low blood glucose (hypoglycemia)

What side effects are possible with this medication?

Many medications can cause side effects. A side effect is an unwanted response to a medication when it is taken in normal doses.

Side effects can be mild or severe, temporary or permanent. The side effects listed below are not experienced by everyone who takes this medication. If you are concerned about side effects, discuss the risks and benefits of this medication with your doctor.

The following side effects have been reported by at least 1% of people taking this medication. Many of these side effects can be managed, and some may go away on their own over time.

Contact your doctor if you experience these side effects and they are severe or bothersome. Your pharmacist may be able to advise you on managing side effects.

  • redness, itching, or swelling at the site of injection

Although most of these side effects listed below don’t happen very often, they could lead to serious problems if you do not check with your doctor or seek medical attention.

Check with your doctor as soon as possible if any of the following side effects occur:

  • early diabetic acidosis
    • drowsiness
    • flushed face
    • loss of appetite
    • thirst
  • signs of low blood glucose:
    • anxiety
    • blurred vision
    • confusion
    • difficulty concentrating
    • difficulty speaking
    • dizziness
    • drowsiness
    • fast heartbeat
    • headache
    • hunger
    • nausea
    • nervousness
    • numbness or tingling of the lips or tongue
    • sweating
    • tiredness
    • trembling
    • weakness
  • skin changes
    • lipoatrophy; depressions in the skin at the injection site
    • lipohypertrophy; thickening of the skin at the injection site

Stop taking the medication and seek immediate medical attention if any of the following occur:

  • rash or blisters all over body
  • severe diabetic acidosis:
    • coma
    • death
    • heavy breathing
    • loss of consciousness
    • rapid pulse
  • symptoms of a serious allergic reaction (e.g., swelling of the face or throat, difficulty breathing, wheezing, or itchy skin rash)
  • unconsciousness

Some people may experience side effects other than those listed. Check with your doctor if you notice any symptom that worries you while you are taking this medication.

Are there any other precautions or warnings for this medication?

Before you begin using a medication, be sure to inform your doctor of any medical conditions or allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should use this medication.

Allergic reactions: If you notice signs of a serious allergic reaction (e.g., swelling of the face or throat, difficulty breathing, wheezing, or itchy skin rash), stop using the medication and seek immediate medical attention.

Appearance of insulin: The contents of the vial of insulin lispro should be clear and colourless. Do not use this medication if you notice anything unusual about its appearance.

Blood glucose monitoring: It is important for anyone using insulin to monitor their blood glucose levels regularly, as recommended by their doctor or diabetes educator. It is especially important to test blood glucose more often when your insulin dose or schedule changes, or when you are ill or under stress. If blood tests consistently show high or low blood glucose levels, contact your doctor or diabetes educator.

Changes at injection site: Fatty tissue under the skin at the injection site may shrink or thicken if you inject yourself too often at the same site. To help avoid this effect, change the site with each injection. Talk to your doctor or diabetes educator if you notice your skin pitting or thickening at the injection site.

Changes in insulin requirements: Many things can affect blood glucose levels and insulin requirements, including:

  • certain medical conditions (e.g., infections, thyroid conditions, kidney or liver disease)
  • certain medications that increase or decrease blood glucose levels
  • diet
  • exercise
  • illness
  • injury
  • stress
  • surgery
  • travelling over time zones

It is important that your doctor know about your current health situation and any changes that may affect the amount of insulin you need. Blood glucose should be monitored regularly as recommended by your doctor or diabetes educator.

Diabetes identification: It is important to either wear a bracelet (or necklace) or carry a card indicating you have diabetes and are taking insulin.

Family and friends: Educate your family and friends about the signs and symptoms of hypoglycemia (low blood glucose). Keep a glucagon kit available and instruct them on its proper use in case you experience severe low blood glucose and lose consciousness.

High blood glucose (hyperglycemia): Hyperglycemia can occur if not enough insulin is used or if you routinely forget to use your insulin. If this is not treated, it can result in diabetic ketoacidosis or coma, which can be fatal. Ability to concentrate and react, as well as vision changes, are affected by high levels of blood glucose. The first symptoms of hyperglycemia include an increased need to urinate, nausea, vomiting, drowsiness, excessive thirst, weight loss, loss of appetite, and an acetone or fruity odour to the breath. If you notice any of these symptoms, contact your doctor immediately.

Low blood glucose (hypoglycemia): Hypoglycemia may occur if too much insulin is used, if meals are missed, or if you exercise more than usual. Symptoms of mild-to-moderate hypoglycemia may occur suddenly and can include cold sweat, nervousness or shakiness, fast heartbeat, headache, hunger, confusion, lightheadedness, weakness, and numbness or tingling of the tongue or lips. Mild-to-moderate hypoglycemia may be treated by eating foods or drinks that contain sugar. People taking insulin should always carry a quick source of sugar, such as hard candies, glucose tablets, juice, or regular soft drinks (not diet soft drinks).

Signs of severe hypoglycemia can include disorientation, loss of consciousness, and seizures. People who are unable to take sugar by mouth or who are unconscious may require an injection of glucagon or treatment with intravenous (into the vein) glucose.

Pregnancy: It is essential to maintain good blood glucose control throughout pregnancy. Insulin requirements usually decrease during the first trimester and increase during the second and third trimesters.

Breast-feeding: Breast-feeding mothers may require adjustments in their insulin dose or diet.

Children: The safety and effectiveness of using this medication have not been established for children less than 3 years of age.

What other drugs could interact with this medication?

For a full list of interactions, use the Drug Interaction Checker available on the website.

If you are taking other medications, speak with your doctor or pharmacist. Depending on your specific circumstances, your doctor may want you to:

  • stop taking one of the medications,
  • change one of the medications to another,
  • change how you are taking one or both of the medications, or
  • leave everything as is.

An interaction between two medications does not always mean that you must stop taking one of them. Speak to your doctor about how any drug interactions are being managed or should be managed.

Tell your doctor or prescriber about all prescription, over-the-counter (non-prescription), and herbal medications you are taking. Also tell them about any supplements you take. Since caffeine, alcohol, the nicotine from cigarettes, or street drugs can affect the action of many medications, you should let your prescriber know if you use them.

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Last Updated: 12/07/2024