Regular Insulin: Presentation, Indications, Mechanism of Action, Dosage, Side Effects, Warnings, Contraindications and Interactions

It is a man-made form of insulin.

Regular (human) insulin injectable solution is available as brand name drugs, it is not available in generic form.

Regular injectable (human) insulin is used along with a healthy diet and exercise to control high blood sugar caused by type 1 or type 2 diabetes.

Ingredients of regular insulin

  • Human insulin.


Regular insulin comes in two forms: injectable solution, and intravenous injection of human insulin (100 units / ml and 500 units / ml).

Indications for regular insulin

Regular insulin is indicated for the control of hyperglycemia in patients suffering from diabetes mellitus, with insulin requirements greater than 200 units per day.

The unlabeled use is in the treatment of hyperkalemia.

Mechanism of action

Reduces blood glucose by stimulating glucose uptake in skeletal muscle and fat, inhibiting hepatic glucose production.

Other actions of insulin: inhibition of lipolysis and proteolysis, improved protein synthesis.


Regular insulin is usually given three or more times a day before meals.

The patient should eat their food within 30 minutes after the injection.

Average insulin requirements range from 0.5 to 1 unit / kg per day.

If insulin therapy is just starting, the dose may be lower, between 0.2 and 0.4 units / kg per day.

Regular insulin is injected subcutaneously, under the skin in the fatty part of your abdomen, thigh, buttocks, or the back of your arm.

For hyperglycemia, the loading dose is 0.1 units / per kg intravenous injection or slow intravenous infusion as ordered.

The maintenance dose is 0.02 to 0.1 units per kg per hour by continuous intravenous infusion (titration with hourly determinations of serum glucose and 4 determinations per hour of serum potassium until these levels are stable).

In cases of hyperkalemia, the dose is 0.05 to 0.1 units per kg per hour by continuous intravenous infusion (titration with serum glucose measurements per hour and serum potassium measurements 4 per hour until these levels are stable).

Side effects of regular insulin

Common side effects

The most common side effects that occur with regular (human) insulin include:

  • Swelling of the arms and legs.
  • Weight gain.
  • Low blood sugar ( hypoglycemia ).

This drop in blood sugar needs to be treated and symptoms can include:

  • Perspiration.
  • Dizziness or lightheadedness
  • Instability.
  • Hungry.
  • Fast heart rate
  • Tingling in your hands, feet, lips, or tongue.
  • Trouble concentrating or confusion
  • Blurry vision.
  • Talk confused.
  • Anxiety, irritability, or mood swings.

Injection site reactions

Do not inject insulin into red, inflamed, or itchy skin. Symptoms at the injection site may include:

  • Redness
  • Swelling.
  • Itch.

Skin changes at the injection site (lipodystrophy)

Continually change where insulin is injected on your skin to help reduce the chance of developing these skin changes.

If you have these skin changes, do not inject insulin into this skin type. Symptoms may include shrinking or thickening of the skin at injection sites.

Serious side effects

Seek emergency medical attention if you have symptoms such as:

  • Difficulty breathing, fast heartbeat, feeling like you might pass out, or swelling of the tongue or throat.
  • Allergic reactions such as skin rash, itching or hives , swelling of the face, lips or tongue.
  • Respiratory problems.
  • Signs and symptoms of high blood sugar, such as dizziness, dry mouth, dry skin, fruity breath, nausea, stomach pain, increased hunger or thirst, increased urination.
  • Signs and symptoms of low blood sugar, such as feeling anxious , confusion, dizziness, increased hunger, unusually weak or tired, sweating, shaking, cold, irritability, headache, blurred vision, fast heartbeat, loss of conscience.

Warnings and Contraindications

This medicine should not be used if:

  • You have an insulin allergy, or if you have an episode of hypoglycemia (low blood sugar).
  • In people with kidney disease, because the kidneys remove insulin from the body, if the kidneys do not work well, insulin can build up in the body and cause low blood sugar.
  • In people with liver disease, if you have liver failure, this drug can build up in the body.
  • In people with heart failure , since taking certain diabetes medicines called thiazolidinediones with regular (human) insulin can make your heart failure worse.
  • In people with hypokalemia, insulin can cause a change in potassium levels, which can lead to low potassium in the blood. If you are using potassium-lowering medications with regular (human) insulin, your doctor will check your blood sugar and potassium frequently.
  • In pregnant women: Studies have not shown any risk to the fetus if the mother uses regular (human) insulin. Discuss with the physician whether the benefit justifies the potential risk.
  • In women who are breastfeeding: Insulin can pass into breast milk and be broken down by the child’s stomach. Insulin does not cause side effects in children who are breastfed by mothers with diabetes.
  • In children: Children with type 1 diabetes may be more likely to have low blood sugar than adults with type 1 diabetes. Children should be monitored closely with this medicine.

Regular insulin interactions

Beta-blocker medications such as metoprolol, propanolol, eye drops such as timolol, can prevent the fast heartbeat that is often felt when blood sugar drops too low (hypoglycemia).

Before starting, stopping, or changing any medicine, talk to your doctor about how the medicine can affect your blood sugar level.