NovoLog FlexPen Side Effects
Generic name: insulin aspart
Medically reviewed by Drugs.com. Last updated on Oct 15, 2022.
Note: This document contains side effect information about insulin aspart. Some dosage forms listed on this page may not apply to the brand name NovoLog FlexPen.
Applies to insulin aspart: solution.
Serious side effects of NovoLog FlexPen
Along with its needed effects, insulin aspart (the active ingredient contained in NovoLog FlexPen) 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 aspart:
- behavior change similar to being drunk
- bladder pain
- bloody or cloudy urine
- blurred vision
- cold sweats
- difficult, burning, or painful urination
- difficulty with thinking
- dizziness or lightheadedness
- excessive hunger
- fast heartbeat
- frequent urge to urinate
- irritability or abnormal behavior
- lower back or side pain
- restless sleep
- slurred speech
- tingling in the hands, feet, lips, or tongue
- Depression of the skin at the place of injection
- dryness of the mouth
- fast or weak pulse
- feeling of pressure, itching, redness, soreness, stinging, swelling, or tingling at the place of injection
- increased thirst
- irregular heartbeat
- loss of appetite
- mood or mental changes
- muscle cramps or pain
- skin rash or itching over the whole body
- thickening of the skin at the place of injection
- trouble breathing
- unusual tiredness or weakness
- Bloating or swelling of the face, arms, hands, lower legs, or feet
- difficulty in breathing or swallowing
- rapid weight gain
- redistribution or accumulation of body fat
- swelling of the face, throat, or tongue
- unusual weight gain or loss
Other side effects of NovoLog FlexPen
Some side effects of insulin aspart 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:
- Back pain
- body aches or pain
- ear congestion
- loss of voice
- muscle aches
- sore throat
- stuffy or runny nose
For Healthcare Professionals
Applies to insulin aspart: injectable solution, subcutaneous solution.
Very rare (less than 0.01%): Anaphylaxis
Common (1% to 10%): Allergic skin manifestations
Frequency not reported: Allergic reactions[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, allergic reactions were reported in 0.7% (10/1394) patients receiving insulin aspart.
Clinical trials with Fiasp(R) reported generalized hypersensitivity reactions at 0.2% (comparator 0.1%). Anaphylactic reactions were not reported. Allergic skin manifestations were reported at 1.5% (comparator 1.4%) and included eczema, rash, pruritic rash, urticaria, and dermatitis.[Ref]
Very common (10% or more): Hypoglycemia
Frequency not reported: Weight gain[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]
Localized cutaneous amyloidosis at the injection site has been reported with resultant hyperglycemia with repeated insulin injections into that area; hypoglycemia has been reported with a sudden change to an unaffected injection site.
Common (1% to 10%): Injection site reactions (including rash, redness, inflammation, pain, itching, and bruising)
Frequency not reported: Lipodystrophy (including lipohypertrophy, lipoatrophy)
Postmarketing reports: Localized cutaneous amyloidosis at injection site
Insulin may cause sodium retention and edema, especially as metabolic control is improving.[Ref]
Common (1% to 10%): Chest pain
Uncommon (0.1% to 1%): Peripheral edema[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%): Skin disorder, eczema, dermatitis
Uncommon (0.1% to 1%): Urticaria, rash
Frequency not reported: Lipodystrophy including lipohypertrophy and lipoatrophy[Ref]
Common (1% to 10%): Onychomycosis
Frequency not reported: Anti-insulin antibody titers[Ref]
The clinical significance of the development of these antibody titers is unknown.[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]
Very common (10% or more): Headache (up to 12%)
Common (1% to 10%): Hyporeflexia, sensory disturbance
Rare (less than 0.1%): Painful peripheral neuropathy[Ref]
Common (1% to 10%): Back pain[Ref]
Very common (10% or more): Nasopharyngitis (23%)
Common (1% to 10%): Upper respiratory infection[Ref]
Frequently asked questions
- Humalog vs Novolog (Novalog): What's the difference?
- How and where should I inject insulin?
- What is the difference between Fiasp and NovoLog?
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More about NovoLog FlexPen (insulin aspart)
- Check interactions
- Pricing & coupons
- Reviews (4)
- Drug images
- Latest FDA alerts (2)
- Dosage information
- During pregnancy
- Drug class: insulin
- En español
Related treatment guides
1. "Product Information. NovoLOG (insulin aspart)." Novo Nordisk Pharmaceuticals Inc (2022):
2. Cerner Multum, Inc. "UK Summary of Product Characteristics." O 0
3. Cerner Multum, Inc. "Australian Product Information." O 0
4. "Product Information. Fiasp (insulin aspart)." Novo Nordisk Pharmaceuticals Inc (2017):
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.