Insulin NPH: What is it? Uses, Administration, Mechanism of Action and Adverse Reactions

It is essential for the metabolism and homeostasis of carbohydrates, fats and proteins.

This artificial insulin product is the same as human insulin. It replaces the insulin that your body would normally make.

Nph (neutral protamine hagedorn) insulin is an intermediate-acting insulin with a longer onset and duration of activity compared to regular insulin; hormone secreted by pancreatic beta cells of the islets of Langerhans.

Uses of nph insulin

Also known as isophane insulin, it is used with a proper diet and exercise program to control high blood sugar in people with diabetes.

Controlling high blood sugar helps prevent kidney damage, blindness, nerve problems, loss of limbs, and problems with sexual function.

Proper diabetes control can also lower your risk of having a heart attack or stroke.

It is an intermediate-acting insulin (isophane). It starts to work more slowly but lasts longer than regular insulin.

Isophane insulin works by helping blood sugar (glucose) enter cells so your body can use it for energy.

Isophane insulin is often used in combination with a shorter-acting insulin. It can also be used alone or with other oral diabetes medications (such as metformin).

Common brand names

  • Humulin N.
  • Novolin N.
  • ReliOn.

How to supply it

Nph insulin (Humulin N / Novolin N) is presented and supplied as a subcutaneous suspension: 1 ml, 100 U.


The total daily dose is given 1 to 2 injections per day, 30 to 60 minutes before food or bedtime.

Initially, some patients may be given a single daily dose 30 to 60 minutes before breakfast, but blood glucose may not be controlled for 24 hours with this regimen.

Babies, children and adolescents

Insulin requirements are highly variable and must be individualized based on patient-specific factors and type of insulin regimen.

During the partial remission phase, the total daily requirement for combined insulin is usually less than 0.5 units / kg / day.

Prepubertal children (outside of the partial remission phase) generally require 0.7 to 1 unit / kg / day. During puberty, insulin requirements are much higher, often between 1 and 2 units / kg / day.

Use isophane insulin (NPH) in combination with short-acting or rapid-acting insulin as part of twice-daily or basal bolus regimens.

Adults and adolescents (pregnant women)

Dosage guidelines are variable and must be individualized.

The suggested initial daily insulin requirements are approximately 0.3 to 0.7 units / kg / day; Requirements generally increase during the second and third quarters (ie 0.8 units / kg / day or more).

The daily dose is usually divided into 2 to 3 doses and given in varying ratios of NPH: regular insulin. Intensive therapy (more than 3 injections daily) is rarely needed.

Dose adjustments are based on fasting and postprandial blood glucose level.

Based on the goals defined in the ADA or ACOG guidelines, typical 2-hour postprandial glucose goals are 120 mg / dL or less.

To prevent fetal and maternal complications, careful control and monitoring of blood glucose is required.

During labor, insulin requirements decrease and generally return to normoglycemia several days after delivery.

Insulin is often stopped during or after delivery; monitor blood glucose during labor and the days after delivery; Follow-up at 6 weeks postpartum.

Mechanism of action of nph insulin

Endogenous insulin regulates carbohydrate, fat, and protein metabolism by several mechanisms; In general, insulin promotes storage and inhibits the breakdown of glucose, fats, and amino acids.

Insulin reduces glucose concentrations by facilitating glucose uptake in muscle and adipose tissue and by inhibiting hepatic glucose production (glycogenolysis and gluconeogenesis).

Insulin also regulates fat metabolism by increasing fat storage (lipogenesis) and inhibiting the mobilization of fat for energy in adipose tissues (lipolysis and free fatty acid oxidation).

Finally, insulin participates in the regulation of protein metabolism by increasing protein synthesis and inhibiting proteolysis in muscle tissue.

Type 1 diabetes mellitus is caused by insulin deficiency, while type 2 diabetes mellitus is caused by a combination of insulin resistance and deficiency.

Biosynthetic insulin is used as replacement therapy in patients with diabetes mellitus to temporarily restore their ability to use fat, carbohydrates, and protein, and to convert glycogen to fat.

The administration of insulin also allows these patients to replenish their glycogen stores in the liver.

Commercially available insulin is prepared using recombinant DNA technology using Saccharomyces cerevisiae (baker’s yeast) or enzymatic modification of beef or pork to create a product identical in structure and function to endogenous human insulin.


Isophane insulin (NPH) is administered subcutaneously only by intermittent injections. Endogenous insulin is widely distributed throughout the body.

A small portion is inactivated by peripheral tissues, but the majority is metabolized by the liver and kidneys.

Insulin is filtered and reabsorbed by the kidneys; the plasma half-life of endogenous human insulin is approximately 5 to 6 minutes.

Subcutaneous route

After subcutaneous administration, the onset of glucose lowering activity begins 1.5 hours after injection, with the greatest blood sugar lowering effect between 4 and 12 hours after injection.

The effects can last up to 24 hours.

Adverse reactions of nph insulin


  • Headache.
  • Acne.
  • Weight gain.
  • Injection site reaction.
  • Itching.
  • Urticaria.
  • Diaforesis.
  • Insulin resistance


  • Hypoglycemia
  • Somogyi effect.
  • Wheezing
  • Dyspnoea.
  • Tachycardia.
  • Hypertension.
  • Peripheral edema.
  • Lipodystrophy.


  • Insulin crash.
  • Anaphylactoid reactions.


  • Avoid exposure to heat.
  • Discard if product has been frozen.
  • Discard within 14 days of first use.
  • Protect against freezing.
  • Protect from light.

Store in the refrigerator (36 to 46 degrees F) or at room temperature, not to exceed 86 degrees F.