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Humalog KwikPen Side Effects

Generic name: insulin lispro

Medically reviewed by Last updated on Nov 7, 2022.

Note: This document contains side effect information about insulin lispro. Some dosage forms listed on this page may not apply to the brand name Humalog KwikPen.

Applies to insulin lispro: solution.

Serious side effects of Humalog KwikPen

Along with its needed effects, insulin lispro (the active ingredient contained in Humalog KwikPen) may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur while taking insulin lispro:

More common

  • Anxious or nervous feeling
  • behavior change similar to being drunk
  • blurred vision
  • chills
  • cold sweats
  • confusion or difficulty thinking
  • depression
  • dizziness or lightheadedness
  • drowsiness
  • excessive hunger
  • fast heartbeat
  • fever
  • headache
  • irritability or abnormal behavior
  • lower back or side pain
  • nightmares
  • painful or difficult urination
  • restless sleep
  • seizures
  • shakiness
  • slurred speech
  • tingling in the hands, feet, lips, or tongue

Less common

  • Dry, red, hot, or irritated skin


  • Depression of the skin at the injection site
  • dryness of the mouth
  • fast or weak pulse
  • itching, redness, or swelling at the injection site
  • muscle cramps or pain
  • nausea
  • skin rash or itching over the whole body
  • sweating
  • thickening of the skin at the injection site
  • trouble breathing
  • unusual tiredness or weakness
  • vomiting

Incidence not known

  • Bloating or swelling of the face, arms, hands, lower legs, or feet
  • decreased urine
  • difficulty with swallowing
  • dizziness, faintness, or lightheadedness when getting up suddenly from a lying or sitting position
  • fast, pounding, or irregular heartbeat or pulse
  • hives or itching skin
  • puffiness or swelling of the eyelids or around the eyes, face, lips, or tongue
  • redistribution or accumulation of body fat
  • tightness in the chest
  • unusual weight gain or loss

Other side effects of Humalog KwikPen

Some side effects of insulin lispro may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects.

Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common

  • Body aches or pain
  • congestion
  • runny nose
  • sneezing
  • sore throat
  • stuffy nose
  • tender, swollen glands in the neck
  • unusual tiredness or weakness
  • voice changes

Incidence not known

  • Redness, swelling, or itching at the injection site

For Healthcare Professionals

Applies to insulin lispro: injectable solution, subcutaneous solution.


Adverse reactions observed have included hypoglycemia, allergic reactions, local injection site reactions, lipodystrophy, rash, and pruritus.[Ref]


Weight gain has been reported with insulin therapy and has been attributed to the anabolic effects of insulin and the decrease in glucosuria.[Ref]

Very common (10% or more): Hypoglycemia

Frequency not reported: Weight gain[Ref]


Hypersensitivity side effects have included both local and systemic reactions. Anaphylaxis has been reported. Local reactions have presented as erythema, local edema, and pruritus at the injection site. Most minor reactions to insulin at the injection site resolve in a few days to a few weeks.

Generalized allergy to insulin may present as a whole body rash, dyspnea, wheezing, hypotension, tachycardia, or diaphoresis. In clinical trials, pruritus (with or without rash) was seen in 17 patients receiving human insulin (n=2969) and 30 patients receiving insulin lispro (the active ingredient contained in Humalog KwikPen) (n=2944).[Ref]

Frequency not reported: Allergic reactions including anaphylaxis[Ref]


Common (1% to 10%): Infusion site reactions

Rare (less than 0.1%): Catheter occlusions/month[Ref]


Uncommon (0.1% to 1%): Refraction disorder, worsening of diabetic retinopathy[Ref]

Rapid improvement in glucose control has been associated with a transitory, reversible ophthalmologic refraction disorder and worsening of diabetic retinopathy. However, long-term glycemic control decreases the risk of diabetic retinopathy.[Ref]

Nervous system

Very common (10% or more): Headache (up to 29.6%)

Rare (less than 0.1%): Painful peripheral neuropathy[Ref]

Rapid improvement in glucose control has been associated with a transitory, reversible acute painful peripheral neuropathy. However, long-term glycemic control decreases the risk.[Ref]


Very common (10% or more): Flu syndrome (up to 34.6%), infection (up to 13.6%)

Frequency not reported: Anti-insulin antibody titers[Ref]

The clinical significance of the development of these antibody titers is unknown.[Ref]


Insulin may cause sodium retention and edema, especially as metabolic control is improving.[Ref]

Frequency not reported: Peripheral edema[Ref]


Uncommon (0.1% to 1%): Urticaria, rash

Frequency not reported: Lipodystrophy including lipohypertrophy and lipoatrophy[Ref]

Long-term use of insulin may cause lipodystrophy at the site of repeated injection. Lipodystrophy includes lipohypertrophy, a thickening of adipose tissue, and lipoatrophy, thinning of adipose tissue.[Ref]


Common (1% to 10%): Nausea, diarrhea, abdominal pain[Ref]


Common (1% to 10%): Urinary tract infection, dysmenorrhea[Ref]


Common (1% to 10%): Myalgia[Ref]


Very common (10% or more): Pain (up to 19.8%)

Common (1% to 10%): Fever[Ref]


Very common (10% or more): Pharyngitis (up to 33.3%), rhinitis (up to 24.7%), increased cough (up to 17.3%)

Common (1% to 10%): Sinusitis, bronchitis[Ref]

Frequently asked questions


1. "Product Information. Humalog (insulin lispro)." Lilly, Eli and Company (2002):

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

Further information

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

Some side effects may not be reported. You may report them to the FDA.