Insulin Lispro Protamine-Insulin Lispro

Reviewed on 8/29/2022

What Are Insulin Lispro Protamine/Insulin Lispro and How Does It Work?

Insulin Lispro Protamine/Insulin Lispro is a combination medication used for the treatment of type 2 diabetes mellitus.

  • Insulin Lispro Protamine/Insulin Lispro is available under various brand names: HumaLOG Mix 50/50, HumaLOG Mix 50/50 KwikPen, HumaLOG Mix 50/50 Pen, HumaLOG Mix 75/25, HumaLOG Mix 75/25 KwikPen, HumaLOG Mix 75/25 Pen, Insulin Lispro Protamine-Insulin Lispro Mix75/25 KwikPe

What Are Side Effects Associated with Using Insulin Lispro Protamine/Insulin Lispro?

Common side effects of Insulin Lispro Protamine/Insulin Lispro include:

  • low blood sugar;
  • itching, mild skin rash; or
  • thickening or hollowing of the skin at the injection site.

Serious side effects of Insulin Lispro Protamine/Insulin Lispro include:

  • redness or swelling at the injection site, 
  • itchy skin rash over the entire body, 
  • trouble breathing,
  • fast heartbeats,
  • a light-headed feeling, 
  • swelling in the tongue or throat.
  • fluid retention--weight gain, swelling in the hands or feet, feeling short of breath; or
  • low potassium--leg cramps, constipation, irregular heartbeats, fluttering in your chest, increased thirst or urination, numbness or tingling, muscle weakness, or limp feeling.

Rare side effects of Insulin Lispro Protamine/Insulin Lispro include:

  • none

Seek medical care or call 911 at once if you have the following serious side effects:

  • Severe headache, confusion, slurred speech, arm or leg weakness, trouble walking, loss of coordination, feeling unsteady, very stiff muscles, high fever, profuse sweating, or tremors;
  • Serious eye symptoms such as sudden vision loss, blurred vision, tunnel vision, eye pain or swelling, or seeing halos around lights;
  • Serious heart symptoms include fast, irregular, or pounding heartbeats; fluttering in the chest; shortness of breath; sudden dizziness, lightheartedness, or passing out.

This is not a complete list of side effects and other serious side effects or health problems that may occur because of the use of this drug. Call your doctor for medical advice about serious side effects or adverse reactions. You may report side effects or health problems to FDA at 1-800-FDA-1088.

What Are Dosages of the Insulin Lispro Protamine/Insulin Lispro?

Adult dosage

Subcutaneous injection

  • (75 units/25 units)/mL
  • (50 units/50 units)/mL

Diabetes Mellitus

Adult dosage

  • The dose regimen varies among patients depending on metabolic needs; typical daily insulin requirements range between 0.5-1 unit/kg
  • Administer SC twice daily (i.e., before breakfast and evening meal); each dose intended to cover 2 meals or a meal and snack

Dosage Considerations – Should be Given as Follows: 

  • See “Dosages”

What Other Drugs Interact with Insulin Lispro Protamine/Insulin Lispro?

If your medical doctor is using this medicine to treat your pain, your doctor or pharmacist may already be aware of any possible drug interactions and may be monitoring you for them. Do not start, stop, or change the dosage of any medicine before checking with your doctor, health care provider, or pharmacist first.

  • Insulin Lispro Protamine/Insulin Lispro has no noted severe interactions with any other drugs.
  • Insulin Lispro Protamine/Insulin Lispro has no noted serious interactions with any other drugs.
  • Insulin Lispro Protamine/Insulin Lispro has no noted moderate interactions with any other drugs.
  • Insulin Lispro Protamine/Insulin Lispro has no noted minor interactions with any other drugs.

This information does not contain all possible interactions or adverse effects. Visit the RxList Drug Interaction Checker for any drug interactions. Therefore, before using this product, tell your doctor or pharmacist about all your products. Keep a list of all your medications with you and share this information with your doctor and pharmacist. Check with your health care professional or doctor for additional medical advice, or if you have health questions or concerns.

What Are Warnings and Precautions for Insulin Lispro Protamine/Insulin Lispro?


  • Allergic to insulin lispro
  • Hypoglycemia
  • Younger than 18 years old

Effects of drug abuse

  • None

Short-Term Effects

  • See “What Are Side Effects Associated with Using Insulin Lispro Protamine/Insulin Lispro?”

Long-Term Effects

  • See “What Are Side Effects Associated with Using Insulin Lispro Protamine/Insulin Lispro?”


  • Never share an injection pen, cartridge, or syringe with another person, even if the needle has been changed.
  • 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.
  • Do not inject this medicine into skin that is damaged, tender, bruised, pitted, thickened, scaly, or has a scar or hard lump.
  • 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 diseases to pass from one person to another.
  • Use a disposable needle and syringe only once. Follow any state or local laws about throwing away used needles and syringes. Use a puncture-proof "sharps" disposal container (ask your pharmacist where to get one and how to throw it away). Keep this container out of the reach of children and pets.
  • 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.
  • Insulin is only part of a complete treatment program that may also include diet, exercise, weight control, regular blood sugar testing, and special medical care. Follow your doctor's instructions very closely.
  • This medicine should look cloudy. Do not use the medicine if it looks clear or has particles in it. Call your pharmacist for new medicine.
  • 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.

Pregnancy & Lactation

  • The limited available data on pregnant women are insufficient to inform a drug-associated risk of adverse developmental outcomes; published studies during pregnancy have not reported an association between the drug and induction of major birth defects, miscarriage, or adverse maternal or fetal outcomes; there are risks to mother and fetus associated with poorly controlled diabetes in pregnancy
  • Poorly controlled diabetes in pregnancy increases the maternal risk for diabetic ketoacidosis, pre-eclampsia, spontaneous abortions, preterm delivery, stillbirth, and delivery complications; also increases the fetal risk for major birth defects, stillbirth, and macrosomia-related morbidity
  • Lactation
    • There are no data on the presence of the drug in human milk, effects on the breastfed infant, or milk production; one small published study reported exogenous insulin present in human milk; however, there is insufficient information to determine effects on the breastfed infant and no available information on the effects on milk production; the developmental and health benefits of breastfeeding should be considered along with mother’s clinical need for insulin, any potential adverse effects on the breastfed child from the drug or underlying maternal condition.

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