Insulin Safety Center

About insulin

What Is Insulin?

The human body requires energy to function. We receive energy from the foods we eat in the form of protein, fat and carbohydrates, or "carbs." The food we eat is typically converted to sugars. In order for sugar to enter the cell and provide energy, it must bind to a hormone called insulin (IN-su-lin).

Insulin is like a key that "unlocks the door" to enter the cell. If we did not have insulin in our bodies, the sugar could not "unlock the door" to enter the cell. The blood sugar levels would then become very high. When there is not enough insulin to unlock the cell, the sugar stays in the blood and cannot be used to make energy.

If we did not have insulin in our bodies, our blood sugar levels would also become too high. If this happens consistently, it will lead to serious health problems, including heart disease and damage to the nerves, eyes and kidney.

How is Insulin produced?

Insulin is normally produced and secreted by the pancreas. In a healthy individual the pancreas will automatically produce and release insulin into the blood stream when the body senses that blood sugar levels are elevated (after a sweet snack or a large meal). People with diabetes have trouble interacting with insulin which affects the regulation of their blood sugar level. They are normally split into two categories: Type 1 and Type 2 diabetes.

Type 1 Diabetes:

Individuals with Type 1 diabetes have lost the ability to produce insulin. Their pancreas no longer produces insulin and they require insulin from outside of their body in order to regulate their blood sugar levels.

Type 2 Diabetes:

Individuals with Type 2 diabetes have the ability to produce insulin, but their body does not respond to it as well as it should. These individuals may find benefit from eating a healthy diet and exercise to control their blood sugar, and in some cases may refer to using insulin in the later stages of their treatment.

Are there any types of drugs that can interact with or affect insulin?

Although insulin does not actually “interact” with any drugs, there are numerous drugs that can have an impact on someone who uses insulin. For instance, certain medications can have an effect on your blood sugar and may contribute to an increased or decreased insulin requirement.

Medications that can increase your blood sugar include:

•  corticosteroids
•  isoniazid (an anti-fungul medication)
•  certain lipid-lowering drugs (e.g., niacin)
•  estrogens (a hormone)
•  oral contraceptives (oral birth control)
•  phenothiazines
•  thyroid replacement therapy (drugs like levothyroxine, Synthroid are most commonly used)

Medications that can decrease your blood sugar include:

•  oral antidiabetic agents (usually used in Type 2 diabetes)
•  salicylates
•  sulfa antibiotics
•  certain antidepressants (monoamine oxidase inhibitors)
•  angiotensin-converting-enzyme inhibitors (drugs used for blood pressure control, most commonly “lisinopril”, those that end in “-pril”)
•  angiotensin II receptor blocking agents (drugs that end in “-sartan”, beta-adrenergic blockers (drugs used in blood pressure control, end in “-olol”)
•  inhibitors of pancreatic function (e.g., octreotide)
•  Alcohol
•  Herbals such as chromium, garlic and gymnema can also lower your blood glucose

Of note, beta-adrenergic blockers may mask the symptoms of hypoglycemia in some patients, except for sweating.

When using insulin, it is especially important that you notify your doctor or pharmacist before you begin any new medication. This includes both prescription and non-prescription.

Diabetes in Control ( has compiled a list of:
• drugs that cause hyperglycemia
• drugs that cause hypoglycemia
• drugs that cause both hyperglycemia or hypoglycemia
• drugs that can MASK hypoglycemia

Click here to download (pdf format) this list of drugs.

Does insulin have any side effects?

Insulin, like all drugs, may cause some unwanted side effects. These may occur as a reaction to taking too much insulin or as a result of incorrect dosage or interactions with other medications.

The most common and potentially serious thing to consider with insulin therapy is low blood sugar. Other side effects of insulin may include skin reactions (redness, swelling, itching or rash at the site of injection), changes in the distribution of body fat (lipodystrophy), allergic reactions, sodium (salt) retention, weight gain and general body swelling. These reactions however are not extremely common, and the benefit of using insulin outweighs the risk when it comes to blood glucose control.