What is diabetes?

Diabetes is a set of related diseases in which the body cannot regulate the amount of sugar (specifically, glucose) in the blood.

What are the types of diabetes?

The related diseases of diabetes include:

What are examples of insulin preparations available?

Insulin preparations

Examples of rapid acting insulin

  • Apidra (insulin glulisine): Supplied in a cartridge, vial, prefilled pen (Solostar)
  • Novolog (insulin aspart): Supplied in a cartridge, vial, prefilled pen (FlexPen)
  • Humalog: (insulin lispro): Supplied in a cartridge, vial, prefilled pen (Kwik Pen)

Examples of short acting insulin

  • Novolin R, Humulin R (regular insulin): Supplied in a vial
  • Velosulin (insulin with a phosphate buffer): Supplied in a pump device

Examples of intermediate acting insulin

  • Humulin N, Novolin N (NPH): Supplied in a vial, pen (Humulin N pen)

Examples of long acting insulin

  • Lantus (insulin glargine): Supplied in a vial, cartridge (OptiClick), prefilled pen (Solostar)
  • Levemir (insulin detemir): Supplied in a vial, prefilled pen (FlexPen)
  • Tresiba (deglutec injection): Supplied in a vial 

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What is the dosage and how is insulin administrated?

Dosage and Administration of insulin

  • A meal should be consumed within 30 minutes after administering regular insulin
  • Insulin usually is administered by subcutaneous injection into the abdominal wall, thigh, buttocks (gluteal region), or upper arm. Injection sites should be rotated within the same region.
  • Some insulins (for example, regular insulin) also may be administered intravenously.
  • The dose is individualized for each patient.
  • A combination of short or rapid acting and intermediate or long acting insulin typically are used
  • Some patients may develop resistance to insulin and require increasing doses.
  • Multiple daily insulin injections or continuous subcutaneous infusions via a pump closely mimic pancreatic insulin secretion.
  • Insulin sliding scales (doses of insulin that are based on the glucose level ) may be used for managing critically ill hospitalized patients.

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What are the contraindications, warnings, and precautions for insulin?


  • Hypoglycemia (low blood sugar)
  • Hypersensitivity to insulin or its excipients (inactive co-ingredients)

Warnings and Precautions

  • Hypoglycemia may occur and is the most common side effect of insulin treatment.
  • Severe, life-threatening allergic reactions, including anaphylaxis, may occur.
  • Hypokalemia (low blood potassium) may occur because insulin stimulates movement of potassium from blood into cells. Combining insulin with potassium-lowering drugs may increase the risk of hypokalemia.
  • Hepatic (liver) impairment may reduce the insulin requirement.
  • Renal (kidney) dysfunction may reduce the insulin requirement.
  • Illness, emotional disturbance, or other stress may alter the insulin requirement.
  • Intravenous administration increases the risk of hypoglycemia and hypokalemia.

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Which drugs interact with insulin?

Insulin Drug Interactions

How well does insulin treat diabetes?

Efficacy of insulin

  • In a 24 week study of patients with type 1 diabetes, regular human subcutaneous insulin (mean dose = 18.3 IU) before breakfast and dinner plus human insulin isophane suspension twice daily (mean dose = 37.1 IU) reduced HbA1c by 0.4% from baseline and fasting glucose by -6 mg/dl.
  • In a 24 week study of patients with type 2 diabetes, regular human subcutaneous insulin (mean dose = 25.5 IU) before breakfast and dinner plus human insulin isophane suspension twice daily (mean dose = 52.3 IU) reduced HbA1c by 0.6% from baseline and fasting glucose by -6 mg/dl.

What is the mechanism of action (how it works) for insulin?

Pharmacology (mechanism of action) of insulin

Insulin is a hormone secreted by the pancreas. It regulates the movement of glucose from blood into cells. Insulin lowers blood glucose by stimulating peripheral glucose uptake primarily by skeletal muscle cells and fat, and by inhibiting glucose production and release by the liver. Insulin inhibits lipolysis (breakdown of fat), proteolysis (breakdown of proteins), and gluconeogenesis (manufacture of glucose). It also increases protein synthesis and conversion of excess glucose into fat. Insulins used to treat diabetes are pharmacologically similar to the naturally produced hormone. Patients with diabetes are insensitive to insulin and do not produce enough insulin which leads to hyperglycemia and symptoms of diabetes. Exogenous insulin preparations replace insulin in diabetics, increasing the uptake of glucose by cells and reducing the short and long term consequences of diabetes.

Medically Reviewed on 10/28/2019


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