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Humalog Mix 50 / 50 Pen Side Effects

Generic Name: insulin lispro / insulin lispro protamine

Note: This page contains information about the side effects of insulin lispro / insulin lispro protamine. Some of the dosage forms included on this document may not apply to the brand name Humalog Mix 50 / 50 Pen.

Not all side effects for Humalog Mix 50 / 50 Pen may be reported. You should always consult a doctor or healthcare professional for medical advice. Side effects can be reported to the FDA here.

For the Consumer

Applies to insulin lispro / insulin lispro protamine: subcutaneous suspension

In addition to its needed effects, some unwanted effects may be caused by insulin lispro / insulin lispro protamine. In the event that any of these side effects do occur, they may require medical attention.

You should check with your doctor immediately if any of these side effects occur when taking insulin lispro / insulin lispro protamine:

Incidence not known
  • Anxiety
  • blurred vision
  • chills
  • cold sweats
  • coma
  • confusion
  • convulsions
  • cool, pale skin
  • cough
  • decreased urine
  • depression
  • difficulty with swallowing
  • dizziness
  • dry mouth
  • fast heartbeat
  • flushing or redness of the skin
  • headache
  • hives
  • increased hunger
  • increased thirst
  • irregular heartbeat
  • itching
  • loss of appetite
  • muscle pain or cramps
  • nausea or vomiting
  • nervousness
  • nightmares
  • numbness or tingling in the hands, feet, or lips
  • puffiness or swelling of the eyelids or around the eyes, face, lips, or tongue
  • seizures
  • shakiness
  • shortness of breath
  • skin rash
  • slurred speech
  • sweating
  • swelling
  • tightness in the chest
  • unusual tiredness or weakness
  • unusually warm skin
  • wheezing

Some of the side effects that can occur with insulin lispro / insulin lispro protamine may not need medical attention. As your body adjusts to the medicine during treatment these side effects may go away. Your health care professional may also be able to tell you about ways to reduce or prevent some of these side effects. If any of the following side effects continue, are bothersome or if you have any questions about them, check with your health care professional:

Incidence not known
  • Bleeding, blistering, burning, coldness, discoloration of the skin, feeling of pressure, hives, infection, inflammation, itching, lumps, numbness, pain, rash, redness, scarring, soreness, stinging, swelling, tenderness, tingling, ulceration, or warmth at the injection site
  • redistribution or accumulation of body fat

For Healthcare Professionals

Applies to insulin lispro / insulin lispro protamine: subcutaneous suspension


The most common adverse reactions observed with insulin therapy include hypoglycemia, allergic reactions, local injection site reactions, lipodystrophy, rash, and pruritus.[Ref]


Very common (10% or more): Hypoglycemia[Ref]


Uncommon (0.1% to 1%): Local reactions such as redness, swelling, or itching at the injection site
Very rare (less than 0.01%): Systemic reactions[Ref]

Hypersensitivity side effects have included both local and systemic reactions. These reactions are becoming rare (less than 1% of patients) due to the use of biosynthetic human insulin. Local reactions have presented as erythema, swelling, heat, or subcutaneous nodules. They usually occurred within the first two weeks of therapy and then disappear. Systemic allergy is a generalized allergy to insulin which may present as a rash over the whole body, shortness of breath, wheezing, drop in blood pressure, fast pulse, or sweating. Severe cases may be life-threatening.[Ref]


Frequency not reported: Peripheral edema[Ref]

Insulin may cause sodium retention and edema, especially if previously poor metabolic control is improved by intensified insulin therapy.[Ref]


Uncommon (0.1% to 1%): Lipodystrophy
Frequency not reported: Rash, pruritus[Ref]


Frequency not reported: Anti-insulin antibodies[Ref]


Frequency not reported: Weight gain[Ref]

Weight gain has been attributed to the anabolic effects of insulin and the decrease in glycosuria.[Ref]


Frequency not reported: Injection site reactions[Ref]

Injection site reactions including pain, redness, hives, inflammation, bruising, swelling, and itching, may occur. These reactions are usually transitory and may be related to factors other than insulin, such as irritants in the skin cleansing agent or poor injection technique.[Ref]


1. Cerner Multum, Inc. "UK Summary of Product Characteristics." O 0

2. Cerner Multum, Inc. "Australian Product Information." O 0

3. "Product Information. Humalog Mix75/25 (insulin lispro-insulin lispro protamine)" Lilly, Eli and Company, Indianapolis, IN.

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