Insulin Isophane

Reviewed on 8/29/2022

What Is Insulin Isophane and How Does It Work?

Insulin Isophane is an over-the-counter medication used to control blood sugar levels in adults and children with diabetes mellitus.

  • Insulin Isophane is available under various brand names: humulin N, humulin N kwikpen, humulin N Pen, Novolin N, Novolin N flexpen, Novolin N Innolet, Novolin N pen fill, relion/Novolin N, relion/novolin N flexpen 

What Are Side Effects Associated with Using Insulin Isophane?

Common side effects of Insulin Isophane include:

  • Low blood sugar.
  • Weight gain, swelling in the hands or feet.
  • Itching, mild skin rash; or
  • Thickening or hollowing of the skin at the injection site.

Serious side effects of Insulin Isophane include:

  • Redness or swelling at the injection site, 
  • Itchy skin rash over the entire body,
  • Trouble breathing, 
  • Chest tightness, 
  • Light-headed feeling or swelling in the tongue or throat.
  • Fluid retention--weight gain, swelling in the hands or feet, feeling short of breath; or
  • Low potassium--leg cramps, constipation, irregular heartbeats, fluttering in the chest, increased thirst or urination, numbness or tingling, muscle weakness, or limp feeling.

Rare side effects of Insulin Isophane include:

  • None

Seek medical care or call 911 at once if you have the following serious side effects:

  • Severe headache, confusion, slurred speech, arm or leg weakness, trouble walking, loss of coordination, feeling unsteady, very stiff muscles, high fever, profuse sweating, or tremors.
  • Serious eye symptoms such as sudden vision loss, blurred vision, tunnel vision, eye pain or swelling, or seeing halos around lights.
  • Serious heart symptoms such as fast, irregular, or pounding heartbeats; fluttering in the chest; shortness of breath; sudden dizziness, lightheartedness, or passing out.

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


Diabetes is defined best as... See Answer

What Are the Dosages of Insulin Isophane?

Adult and pediatric dosage

Injectable suspension

  • 100 units/mL (3 mL)
  • 100 units/mL (10 mL)

Type 1 Diabetes Mellitus

Adult dosage

  • Usual daily maintenance range is 0.5-1 unit/kg/day SC in divided doses; nonobese may require 0.4-0.6 unit/kg/day; obese may require 0.8-1.2 units/kg/day

Pediatric dosage

  • Aged below 12 years: Safety and efficacy not established
  • Aged above 12 years: Suggested dose is 0.5-1 unit/kg/day SC; use adult dosing; usual daily maintenance range in adolescents is less than 1.2 units/kg/day during growth spurts

Type 2 Diabetes Mellitus

Adult dosage

Suggested guidelines for beginning dose: 0.2 unit/kg/day


  • Give two thirds of daily insulin SC
  • Ratio of regular insulin to NPH insulin 1:2


  • Give one third of daily insulin SC
  • Ratio of regular insulin to NPH insulin 1:1

Dosage Considerations – Should be Given as Follows: 

  • See “Dosages”

What Other Drugs Interact with Insulin Isophane?

If your medical doctor is using this medicine to treat your pain, your doctor or pharmacist may already be aware of any possible drug interactions and may be monitoring you for them. Do not start, stop, or change the dosage of any medicine before checking with your doctor, health care provider, or pharmacist first.

  • Insulin Isophane has severe interactions with the following drug:
  • Insulin Isophane has serious interactions with the following drugs:
  • Insulin Isophane has moderate interactions with at least 125 other drugs.
  • Insulin Isophane has minor interactions with at least 77 other drugs.

This information does not contain all possible interactions or adverse effects. Visit the RxList Drug Interaction Checker for any drug interactions. Therefore, before using this product, tell your doctor or pharmacist about all your products. Keep a list of all your medications with you and share this information with your doctor and pharmacist. Check with your health care professional or doctor for additional medical advice, or if you have health questions or concerns.

What Are Warnings and Precautions for Insulin Isophane?


  • Hypoglycemia (low blood sugar)
  • Hypersensitivity to Insulin Isophane

Effects of drug abuse

  • None

Short-Term Effects

  • See “What Are Side Effects Associated with Using Insulin Isophane?”

Long-Term Effects

  • See “What Are Side Effects Associated with Using Insulin Isophane?”


  • You should not use this medicine if you are having an episode of low blood sugar.
  • Never share an injection pen or syringe with another person, even if the needle has been changed.
  • Tell your doctor if you also take pioglitazone or rosiglitazone (sometimes contained in combinations with glimepiride or metformin). Taking certain oral diabetes medicines while you are using insulin may increase your risk of serious heart problems.

 Pregnancy and Lactation

  • Tell your doctor if you are pregnant. Follow your doctor's instructions about using insulin if you are pregnant or you become pregnant. Controlling diabetes is very important during pregnancy, and having high blood sugar may cause complications in both the mother and the baby.
  • Lactation
    • Available data from published literature suggests that exogenous human insulin products, are transferred into human milk; there are no adverse reactions reported in breastfed infants in the literature; there are no data on effects of exogenous human insulin products, on milk production; the developmental and health benefits of breastfeeding should be considered along with the mother’s clinical need for therapy, and any potential adverse effects on breastfed infant from drug, or from underlying maternal condition. Tell your doctor if you are breastfeeding. 


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

Health Solutions From Our Sponsors