insulin aspart

Medically Reviewed on 5/12/2023

Generic Name: insulin aspart

Brand Names: NovoLog, NovoLog FlexPen, NovoPen Echo, NovoLog FlexTouch, Fiasp

Drug Class: Antidiabetics, Insulins; Antidiabetics, Rapid-Acting Insulins

What is insulin aspart, and what is it used for?

Insulin aspart is a medication used to lower glucose levels and improve glycemic control in adults and children with diabetes mellitus type I and II. Insulin aspart is a structurally similar analog of human insulin, a hormone secreted by the pancreas, and is produced in the lab using recombinant DNA technology. Animal insulins were used in the past, but currently, human insulin is the only type of insulin available in the U.S.

Insulin, released by the pancreas after a meal, regulates the metabolism of carbohydrates, fats and proteins absorbed from food. Reduced insulin secretion or faulty functioning of insulin results in diabetes, a metabolic disorder that impairs the ability of the cells to absorb glucose for energy, resulting in high blood glucose levels (hyperglycemia). Dysfunction of insulin affects the entire body and can damage all organs, particularly, nerves, kidneys and eyes.

Insulin aspart provides the insulin the body requires for regulating glucose metabolism in the body and for maintaining optimal glucose levels. Insulin reduces blood glucose by stimulating the uptake of glucose from blood into the organs and tissues, particularly skeletal muscle, fat cells and the liver. Insulin inhibits glucose production in the liver, inhibits breakdown of fats and proteins, and enhances protein synthesis.

The types of human insulin used to treat diabetes are categorized by the time taken for onset, peak and duration of insulin effects. Insulin aspart is a rapid-acting insulin with onset of effect within 15 minutes, peak effect in 30-90 minutes and duration of 3-7 hours. Insulin aspart is typically administered 5 to 10 minutes before a meal. Insulin aspart may be used in combination with longer-acting insulins for maintaining optimal glycemic control.

Insulin aspart may be administered intravenously in hospitals, with insulin pump implants, or self-administered subcutaneously with needles, pens or jet injectors. Insulin aspart is approved by the FDA for the treatment of type 1 and 2 diabetes in adults and children. Off-label uses of insulin aspart include:


  • Do not administer insulin aspart to patients:
    • With hypersensitivity to any component of insulin aspart
    • During episodes of hypoglycemia
  • Train patients to self-administer insulin aspart and advise them to never share their delivery devices, to avert the risk of bloodborne infections.
  • Insulin aspart has a more rapid onset of action than regular human insulin. Advise patients to eat a meal within 5-10 minutes after the injection.
  • Insulin aspart has shorter duration of activity than regular insulin. Patients with type 1 diabetes will need an additional longer-acting insulin and some patients with type 2 diabetes may also need it.
  • Glycemic status and insulin requirements in patients may change. Insulin requirements may change with change in activity levels, during illness, emotional disturbances, or with other stressors. Glucose levels must be regularly monitored and insulin regimens appropriately adjusted.
  • Changes in insulin regimen can affect glycemic control and cause hyperglycemia or hypoglycemia. Insulin regimen changes should be made under close medical supervision with increased frequency of blood glucose monitoring.
  • Repeated insulin injections into the same areas can cause skin thickening or depression (lipodystrophy) or abnormal protein clumping in the skin (cutaneous amyloidosis). Injecting in these areas can result in hyperglycemia and a sudden change in the injection site (to an unaffected area) may result in hypoglycemia.
  • Hypoglycemia is the most common adverse effect with all insulin therapies.
    • Hypoglycemia can happen suddenly and symptoms differ in patients and may change over time in the same patient.
    • Prolonged or severe hypoglycemia can cause convulsions, unconsciousness, temporary or permanent brain damage, or even death. 
    • Hypoglycemia risk increases in patients with impaired liver or kidney function.
    • Patients with long-standing diabetes, diabetic nerve disease (neuropathy), recurrent hypoglycemia, or patients taking beta-blockers may have reduced awareness of hypoglycemic symptoms.
    • Blood glucose monitoring should be performed more frequently in patients at higher risk for hypoglycemia and patients who have reduced symptomatic awareness of hypoglycemia.
    • Patients and caregivers must be educated to self-monitor glucose levels, recognize and manage hypoglycemia.
  • Failure or malfunction of subcutaneous insulin pump can rapidly lead to hyperglycemia and ketoacidosis. Train patients using subcutaneous insulin pump therapy in administering subcutaneous insulin injections in case of pump failure and ensure they have alternate insulin delivering device available.
  • Insulin causes shift of potassium into the cells and can lead to low blood potassium (hypokalemia), which if untreated, can cause respiratory paralysis and life-threatening irregular ventricular rhythm (ventricular arrhythmia) and death. Monitor potassium levels in patients at risk for hypokalemia.
  • Insulin aspart dose requirements may be reduced in patients with impairment of liver or kidney function.
  • Insulin aspart can cause severe, life-threatening, generalized allergic reactions including anaphylaxis. Discontinue insulin aspart and monitor the patient until symptoms resolve. Do not use in patients who have had hypersensitivity reactions to any component of insulin aspart.
  • Concurrent use with thiazolidinediones, a class of oral antidiabetic drugs, can cause dose-related fluid retention and increase the risk for heart failure. Closely monitor such patients for symptoms of heart failure.
  • Transient increases in anti-insulin antibodies have been observed with insulin therapy, more frequently with insulin aspart than regular insulin. The clinical significance of these antibodies is not known. These antibodies do not appear to cause deterioration in glycemic control or necessitate increases in insulin dose.


Diabetes: What Raises and Lowers Your Blood Sugar Level? See Slideshow

What are the side effects of insulin aspart?

Common side effects of insulin aspart include:

Call your doctor immediately if you experience any of the following symptoms or serious side effects while using this drug:

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

What are the dosages of insulin aspart?

Injectable solution

  • 100 units/mL (NovoLog, Fiasp)

Prefilled syringe

  • 100 units/mL (3mL NovoLog FlexPen, NovoLog FlexTouch, Fiasp FlexTouch)


Type 1 Diabetes Mellitus

  • Improvement of glycemic control in adults and children with diabetes mellitus
  • May administer 0.2-0.6 unit/kg/day in divided doses; conservative doses of 0.2-0.4 unit/kg/day often recommended to reduce risk of hypoglycemia
  • Total maintenance daily insulin requirement may vary; it is usually between 0.5 and 1 unit/kg/day; nonobese may require 0.4-0.6 unit/kg/day; obese may require 0.6-1.2 units/kg/day

Type 2 Diabetes Mellitus

  • Diabetes inadequately controlled by diet, weight reduction, exercise, or oral medication
  • 10 units/day subcutaneously (or 0.1-0.2 units/kg/day) in evening or divided every 12 hours of an intermediate (e.g., NPH) or long-acting insulin at bedtime recommended; conversely, regular insulin or rapid-acting insulin (aspart insulin) before meals also recommended

Dosing Considerations

  • When used in a meal-related SC injection treatment regimen, 50-75% of total insulin requirements may be provided by an intermediate-acting or long-acting insulin; the remainder is divided and provided before or at mealtimes as a rapid-acting insulin, such as insulin aspart
  • Because of insulin aspart’s comparatively rapid onset and short duration of glucose-lowering activity, some patients may require more basal insulin and more total insulin to prevent pre-meal hyperglycemia than they would need when using human regular insulin
  • Dosage must be individualized; blood and urine glucose monitoring is essential in all patients receiving insulin therapy
  • Insulin requirements may be altered during stress or major illness or with changes in exercise, meal patterns, or coadministered drugs

Fiasp only

  • If converting to Fiasp from another mealtime insulin, the change can be done on a unit-to-unit basis

Dosage Modifications

  • Patients with hepatic and renal impairment may be at increased risk of hypoglycemia and may require more frequent dose adjustment and more frequent blood glucose monitoring


Type 1 Diabetes Mellitus

  • Improvement of glycemic control in adults and children with diabetes mellitus
  • May require 0.8-1.2 units/kg/day SC during growth spurts; adolescents may require up to 1.2 units/kg/day; otherwise, may use 0.5-1 unit/kg/day

Dosing Considerations

  • Insulin pens specifically designed for children and adolescents allow for 0.5 unit dosage increments (e.g., NovoPen Echo)
  • Dosage of human insulin, which is always expressed in USP units, must be based on the results of blood and urine glucose tests and must be carefully individualized to optimal effect
  • NovoLog and Fiasp are approved for children, but have not been studied in children younger than 2 years
  • 50-75% of daily insulin requirement may be supplied by intermediate- to long-acting insulin; the remainder is divided and provided before or at mealtimes as a rapid-acting insulin, such as insulin aspart


  • Insulin aspart overdose can cause severe hypoglycemia and hypokalemia.
  • Mild hypoglycemia can be treated with oral glucose and appropriate adjustments in drug dosage, meal patterns and exercise, as required.
  • Severe hypoglycemia with coma, seizure and neurologic impairment may be treated with concentrated intravenous glucose and intramuscular or subcutaneous injection of glucagon. Sustained carbohydrate intake and continued observation of the patient may be required to prevent recurrence of hypoglycemia.
  • Hypokalemia should be corrected with appropriate supplemental potassium.

What drugs interact with insulin aspart?

Inform your doctor of all medications you are currently taking, who can advise you on any possible drug interactions. Never begin taking, suddenly discontinue, or change the dosage of any medication without your doctor’s recommendation.

  • Severe interactions of insulin aspart include:
  • Severe interactions of insulin aspart include:
    • ethanol
    • macimorelin
  • Insulin asparte has moderate interactions with at least 129 different drugs.
  • Insulin asparte has mild interactions with at least 79 different drugs.

The drug interactions listed above are not all of the possible interactions or adverse effects. For more information on drug interactions, visit the RxList Drug Interaction Checker.

It is important to always tell your doctor, pharmacist, or health care provider of all prescription and over-the-counter medications you use, as well as the dosage for each, and keep a list of the information. Check with your doctor or health care provider if you have any questions about the medication.

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Pregnancy and breastfeeding

  • Patients with diabetes who wish to conceive should use adequate contraception until glycemic control is achieved. Rapid-acting insulin aspart is one of the preferred insulins for treating diabetes mellitus in women planning to become pregnant.
  • Good control of diabetes during pregnancy improves maternal and fetal outcomes. Insulin is the preferred treatment of type 1 and type 2 diabetes mellitus in pregnancy, as well as gestational diabetes mellitus, if treatment is required for diabetes control. 
  • Poorly controlled diabetes in pregnancy increases the maternal risk for diabetic ketoacidosis, preeclampsia, spontaneous abortions, preterm delivery, stillbirth and delivery complications, and fetal risks for birth defects and abnormally large growth (macrosomia).
  • Insulin requirements increase as pregnancy progresses and rapidly reduce after delivery. Glucose levels should be carefully monitored and insulin regimens appropriately adjusted in pregnant women.
  • There is not enough information on the presence of insulin aspart in breastmilk, or its effects on milk production and on the breastfed infant.
  • Decision to breastfeed must be made after considering the mother’s clinical need, developmental and health benefits to the infant, and the risk to the breastfed infant from exposure to insulin aspart and the mother’s underlying condition.
  • Nursing mothers may require adjustments in insulin dose.

What else should I know about insulin aspart?

  • Never share your pen, needles, cartridges, syringes or other insulin delivery devices with others even with changed needles, and never use those used by others.
  • Administer your insulin aspart injection exactly as prescribed, any regimen change must be done only under your physician’s supervision.
  • Insulin aspart acts rapidly. Eat a meal within 5-10 minutes after the injection.
  • Rotate your injection sites and do not inject into areas of skin that have scars, pits, lumps, scales, or are tender or bruised.
  • Always check labels before every injection to avoid errors of mix-up with other insulin products.
  • Learn to monitor glucose levels and to recognize symptoms of hypoglycemia. Always carry sweets such as hard candy for immediate use and seek medical help if symptoms don’t resolve.
  • Hypoglycemia can impair concentration ability and reaction time, be cautious about activities such as driving and operating heavy machinery.
  • Report to your physician immediately if you experience any hypersensitivity reactions.
  • Avoid drinking alcohol, it may increase or decrease the effect of insulin aspart.
  • Store insulin aspart and insulin delivery devices safely out of reach of children.
  • In case of overdose, seek medical help immediately or contact Poison Control.


Insulin aspart is a medication used to lower glucose levels and improve glycemic control in adults and children with diabetes mellitus type I and II. Common side effects of insulin aspart include severe hypoglycemia, nose and throat inflammation (nasopharyngitis), viral respiratory tract infection, upper respiratory tract infection, headache, accidental injury, low reflex response (hyporeflexia), sensory disturbance, fungal infection of the nail (onychomycosis), urinary tract infection, back pain, chest pain, and others.

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Medically Reviewed on 5/12/2023