Warnings

Insulin Aspart U-100

Medically Reviewed by Dr. Harshi Dhingra, M.D.

Last Reviewed: Jul 31, 2025

Warnings

Insulin Aspart Risks, Warnings, and Complications

Insulin aspart can cause or worsen health problems in some people. Talk with your doctor or pharmacist about other medications for treating diabetes if you are at an increased risk of adverse reactions from this drug.

RISK OF INFECTION WITH SHARED EQUIPMENT: Never share your insulin equipment, including insulin aspart FlexPen, with others or use other people’s equipment, even if the needle and syringe are changed. Doing so can result in serious blood-borne infections.
HYPOGLYCEMIA (LOW BLOOD SUGAR) OR HYPERGLYCEMIA (HIGH BLOOD SUGAR): Changing your insulin strength or type, or decreasing or increasing insulin levels, can lead to changes in your blood glucose levels, including hypoglycemia (low blood sugar) and hyperglycemia (high blood glucose). Make sure you know the insulin type and strength, manufacturer, injection site, container, and method of administration prescribed by your diabetes care team. Check labels before injecting insulin to ensure you are taking the right type and dose. Your doctor will monitor you closely while adjusting your insulin dose.
Severe hypoglycemia is life-threatening and can result in seizures, loss of consciousness, and even death. Low blood glucose can also lead to accidents and injuries due to an impaired ability to concentrate and a slowed reaction time.
Awareness of hypoglycemia symptoms can be reduced in people with longstanding diabetes, diabetes-related nerve damage, and those taking certain drugs like beta blockers.
Medication errors (accidental mixing of insulin products) can also cause low blood glucose. Always check labels before injecting insulin.
Other factors that can increase the risk of hypoglycemia include exercise and meal patterns, for example, if you delay eating or skip meals, eat different amounts of macronutrients than usual, or engage in strenuous exercise. Frequent blood glucose monitoring can reduce this serious risk. Follow your doctor’s recommendations about how often you should check blood glucose levels.
HYPERSENSITIVITY REACTIONS: There are reports of severe, life-threatening allergic reactions, including anaphylaxis (throat closing), in patients receiving insulin aspart. Stop using insulin aspart and seek emergency medical care if you develop a skin rash, hives, itching, swelling, hoarseness, wheezing, or difficulty breathing or swallowing.
LOCALIZED CUTANEOUS AMYLOIDOSIS AND LIPODYSTROPHY: Localized cutaneous amyloidosis, also called insulin-derived amyloidosis or an insulin ball, is a collection of amyloid protein under the skin surface that can develop at the insulin injection site after repeated injections. Lipodystrophy is an area of fat destruction. Many people with diabetes find insulin injections to be less painful at sites of localized cutaneous amyloidosis and lipodystrophy.
But injecting the medicine into the insulin ball instead of a new injection site can lead to decreased absorption of the drug, which can result in hyperglycemia (high blood sugar).
Suddenly switching to an unaffected area can lead to increased absorption of the drug and hypoglycemia (low blood sugar).
Regularly rotate insulin injection sites and avoid using the same site more often than once every 1-2 weeks.
HYPOKALEMIA: Some people using insulin aspart develop hypokalemia (low blood potassium levels). Your doctor will monitor potassium levels if you are at risk of this complication. Keep all your medical and laboratory appointments while using insulin aspart.
FLUID RETENTION AND HEART FAILURE: Using insulin aspart and oral diabetes medications called thiazolidinediones (TZDs), such as pioglitazone and rosiglitazone, can increase the risk of fluid retention and heart failure. Call your doctor immediately if you develop swelling in the ankles or feet or sudden weight gain. If you develop symptoms of heart failure, you may need to reduce the dose or discontinue insulin aspart.

Precautions Before Starting Insulin Aspart

Tell your doctor if you have ever had an allergic reaction to insulin aspart, any of the active or inactive ingredients in insulin aspart, other insulin products (NPH insulin, Novolin, Humulin, others), or any other drugs. Your pharmacy can give you a list of ingredients.

Give your doctor and pharmacist a complete list of your medications, including prescription medications, over-the-counter medicines, vitamins, nutritional supplements, and herbal remedies. This can help avoid possible interactions between insulin aspart and your other medications.

Give your doctor a complete medical history. Insulin aspart may not be safe for people with certain medical conditions. Tell your doctor if you have nerve damage or vision problems related to diabetes, liver disease, kidney disease, heart failure, or heart disease.

Tell your doctor if you are pregnant, could be pregnant, plan to get pregnant, or are breastfeeding.

Precautions During Use of Insulin Aspart

Keep all your medical and lab appointments while on insulin aspart. Your doctor will adjust your insulin dose based on glycemic control.

Alcohol can affect blood sugar levels. Talk to your doctor about the safety of drinking alcoholic beverages while on insulin aspart.

Tell your doctor if you are under unusual stress, have an infection or illness, or changes in your dietary patterns or activity levels. These can all affect glycemic control. Your provider may adjust your dose of insulin aspart.

Call your doctor if you become pregnant while on insulin aspart.

Tell all your healthcare providers you are on insulin aspart, especially before any surgeries or procedures, including dental treatments.

Talk to your doctor about how often you should monitor blood glucose levels. Make sure you know what to do if you have low blood sugar (hypoglycemia). Ask your healthcare provider if you need to check blood sugar levels before potentially hazardous activities like driving a motor vehicle or operating heavy machinery.

Insulin Aspart Drug Interactions

Taking certain other medications with insulin aspart can affect how it works to control your blood glucose. Clinically significant drug interactions can also increase the risk of severe adverse events. Your healthcare provider may change the dose of your medications, switch you to a different drug, and/or monitor you carefully for adverse effects if there are known interactions between your medicines. The following medications can have interactions with insulin aspart:

Other diabetes medications, including pramlintide (Symlin)
Angiotensin-converting enzyme (ACE) inhibitors
Angiotensin II receptor blockers (ARBs)
Antiarrhythmic drugs like disopyramide
Cholesterol-lowering drugs (fibrates)
Antidepressants (fluoxetine) and monoamine oxidase inhibitors
Drugs used to treat peripheral arterial disease (pentoxifylline)
Salicylates including aspirin
Somatostatin analogs like octreotide
Sulfonamide antibiotics
Atypical antipsychotics such as olanzapine and clozapine
First-generation antipsychotics (phenothiazines)
Corticosteroids
Danazol (used to treat endometriosis)
Diuretics or water pills
Estrogens and progesterones (for example, in oral contraceptives)
Glucagon
Tuberculosis medications such as isoniazid
Niacin (vitamin B3)
Protease inhibitors for HIV/AIDS
Somatropin (human growth hormone analog)
Sympathomimetic drugs such as albuterol, terbutaline, and epinephrine
Thyroid hormones
Clonidine
Pentamidine
Lithium salts
Beta-blockers
Alcohol

The above list may not include all the potential interactions of Insulin Aspart. Give your doctor or pharmacist a complete list of your medications, including prescription drugs, nonprescription drugs, nutritional supplements, and herbal remedies. Also, tell your healthcare professional if you smoke, drink alcohol, or use recreational drugs because some of these substances can cause serious health complications when used with prescription medications.

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