Insulin Therapy for Type 2 Diabetes in Different Situations

Insulin Therapy for Type 2 Diabetes

Insulin therapy for type 2 diabetes may be life-saving in certain situations. Not all type 2 diabetic patients require insulin.

However, as the disease progresses and more and more beta cells of the pancreas die, type 2 diabetic patients become insulin deficient.

The treatment of diabetes type 2 focuses mainly on medications that improve insulin sensitivity (lower insulin resistance) or stimulate the release of insulin from the pancreas.

However, insulin therapy for type 2 diabetes individuals may be required in the following situations:

  • Uncontrolled type 2 diabetes despite maximum oral anti-diabetic medications
  • Organ failures such as kidney, liver, and heart disease
  • Intolerance to oral medications because of gastrointestinal or other side effects
  • During acute medical emergencies such as trauma, surgery, and severe infections
  • Diabetic ketoacidosis
  • Pregnancy, and
  • During the perioperative period
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Insulin therapy for Type 2 Diabetes uncontrolled with oral medications:

This is one of the common reasons individuals with type 2 diabetes mellitus are initiated on insulin therapy.

Oral medications are considered the first line of treatment because:

  • they are least likely associated with weight gain,
  • lower insulin resistance,
  • have cardiovascular and renal benefits,
  • are cheaper, and
  • are easy to use.

However, suppose a diabetic person is on two or three oral diabetes medications and A1C is high despite maximum doses. In that case, insulin therapy may be added or the person may be totally switched to insulin.

Acceptable diabetes medication combinations that may be used are:

Acceptable Diabetes Combinations

MonotherapyTwo drugsThree DrugsFour DrugsFive DrugsSix Drugs
Metformin +Sitagliptin or Vildagliptin +Empagliflozin or Dapagliflozin +Glimepiride or Gliclazide or Glyburide +Pioglitazone ++ Acarbose
Can Add a Basal Insulin like Glargine, Degludec, and Levemir at any step
Metformin +Rybelsus +Empagliflozin or Dapagliflozin +Glimepiride or Gliclazide or Glyburide +Pioglitazone +Acarbose
Can Add a Basal Insulin like Glargine, Degludec, and Levemir at any step

Basal insulin can be added at any of the above steps, however, if premixed insulin such as Insulin 70/30, 75/25, or 50/50, or treatment with basal-bolus insulin is initiated, then sulfonylureas should be discontinued.

In addition, DPP-IV (Sitagliptin and Vildagliptin) should not be combined with a GLP-1 analog. Oral GLP-1 (Rybelsus) and Injectable GLP-1 analogs (Ozempic, Victoza, Trulicity) can be used interchangeably.

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Advanced liver, kidney, and heart diseases:

Most oral diabetes medications are discontinued in patients with advanced liver and kidney diseases.

Insulin is the safest medicine to be used in patients with major organ dysfunction including kidney, liver, and heart disease.

However, novel oral medications can be used even in very advanced kidney and liver diseases.

Organ Dysfunction

Preferred oral drug

Alternative drug (used with caution and reduced dose)

Kidney diseaseLinagliptin
  • Repaglinide and Nateglinide
  • Dapagliflozin and Sitagliptin may be used up to a GFR of 15 ml/min
Liver diseaseNo oral medications are preferred
  • Nateglinide (Not Repaglinide)
  • Acarbose
  • DPP-IV except Vildagliptin

Basal insulin and insulin analog are preferred over human insulin in patients with advanced liver disease because of pharmacokinetic differences [Ref].

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Intolerance to oral medications because of gastrointestinal or other side effects:

Sometimes insulin may not be indicated but diabetic patients may develop side effects to oral diabetes pills.

The most common side effects that may result in treatment discontinuation and necessitate insulin therapy are related to the GI tract.

These include:

Some diabetic patients may start insulin therapy to regain the lost weight as a result of oral diabetes medications.

In addition, SGLT2 inhibitors use may be associated with frequent urinary tract infections. Diabetic patients, especially women who develop frequent urinary tract infections may need to discontinue SGLT2 inhibitors (Dapagliflozin, Empagliflozin, Ertugliflozin, and Canagliflozin).

Metformin and DPP-IV inhibitors (Sitagliptin and Vildagliptin) are associated with gastrointestinal side effects. Pioglitazone may cause retinal and pedal edema. It may also cause fluid retention and worsen heart failure.

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During acute medical emergencies such as trauma, surgery, and severe infections:

Insulin is an anabolic hormone. It helps in healing wounds, weight gain, and cellular proliferation.

During times of acute stress and emergency, it is best to switch to insulin to recover fast from the illness. Because one can achieve the target blood glucose with much ease, insulin therapy is the preferred treatment in such situations.

It is a myth that once insulin treatment is initiated, one can not go back to medicines. One can switch back to insulin any time he/she wishes.

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The target blood glucose during pregnancy is very strict. The ACOG recommends:

  • Fasting blood glucose: 95 mg/dl or less
  • 1-hour blood glucose: 140 mg/dl or less
  • 2 hours post-meal blood glucose: 120 mg/dl or less

The only two drugs that have been approved for use in pregnancy, other than insulin are:

  • Metformin, and
  • Glyburide (Glibenclamide or Daonil).

However, for strict control and even otherwise, insulin is the preferred therapy in pregnant women.

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​​Diabetic Ketoacidosis (DKA)

DKA (diabetic ketoacidosis) is a life-threatening emergency. DKA develops in patients with Type 1 diabetes or Type 2 diabetes who have a relative or absolute insulin deficiency.

Your blood sugar might rise to dangerous levels if your insulin level is too low. because of the high blood glucose, your blood may become acidic and you can get diabetic ketoacidosis (or DKA).

People with Type 1 diabetes and those whose blood glucose levels are over 500 are more likely to experience this.

If you have DKA, your body begins to produce a lot of acids from molecules known as ketones. You may become seriously ill as a result of the acid and high blood sugar.

Another possibility is dehydration (loss of body fluid). By carefully administering the right insulin dose to yourself each day, you can avoid developing DKA.

The only diabetes medicine approved for treating DKA is insulin.

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Insulin therapy when blood sugar is above 500 mg/dl

If you forget to take your diabetic medication, consume too much, or do not exercise enough, hyperglycemia may result. High blood sugar can occasionally be caused by drugs you take for other health issues.

If you are on insulin or other diabetes medications and your blood sugar spikes above 500 mg/dl, what should you do?

1. If you are not feeling well, go straight to the hospital, you might have DKA or hyperosmolar hyperglycemic state.

2. If you are on a stable dose of insulin and suddenly your blood glucose spike to above 500 mg/dl, check your insulin vial. It might have gone bad because of temperature changes.

You need to change your vial and get extra 4 to 6 units as soon as possible or with the next scheduled dose if the time to inject the dose is less than 30 minutes.

Most people usually miss their insulin dose. In such situations, get it injected as soon as possible. You may need to add 4 to 6 units extra. If you have Type 1 diabetes, check your urine or blood ketones first.

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Insulin therapy for blood sugars recorded as “High”

Sugar levels that are recorded as “high” are treated with insulin. “High” sugars may be as high as 1000 to 1200 mg/dl and are associated with strokes and angina.

In such situations, insulin is administered together with fluids and electrolytes, typically intravenously.

Typically a bolus of six units IM (intramuscularly or intravenously) is followed by an infusion of six units each hour (0.1 units/kg for patients weighing less than 60 kg). A higher risk of hypoglycemia is linked to higher dosages.

Once the blood sugar level reaches about 200 mg/dL (11.1 mmol/L) and the blood is no longer acidic, normal insulin therapy may be resumed.

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Insulin therapy when the blood sugar is below 100 mg/dl

When blood sugar levels fall too rapidly or too far below normal, hypoglycemia can happen. If your blood glucose level is less than 70 mg/dL, it is too low.

Hypoglycemia may result from:

  • Increasing your level of activity
  • Consuming alcohol
  • Eating when you shouldn’t be eating in relation to your medication schedule
  • Skipping – failing to complete meals or snacks
  • Overprescribing on diabetic medication

Hypoglycemia is a complication of insulin therapy. It is to be treated through the following measures:

  • 15–20 grams of quick-acting carbs should be consumed or drunk. These are sweet, low-protein, low-fat items that the body may quickly turn into sugar. Try fruit juice, regular soda (not diet), glucose pills or gel, honey, or sweet candies.
  • 15 minutes after therapy, recheck blood sugar levels.
  • Then eat or drink an additional 15 to 20 grams of fast-acting carbohydrates, check your blood sugar levels again in 15 minutes, and if necessary, eat or drink more if levels are still below 70 mg/dL (3.9 mmol/L). In order to raise the blood sugar level to 70 mg/dL (3.9 mmol/L), repeat these procedures.
  • Snack or eat something. Eating a nutritious snack or meal will help avoid further decreases in blood sugar and restore your body’s glycogen stores after it has returned to the normal range.

If you are on insulin treatment and your blood sugars fall to 100 mg/dl or less, you can reduce the dose by 4 to 6 units and get your regular insulin dose.

However, if you have developed symptoms of hypoglycemia or your blood glucose falls to less than 70 mg/dl, you should wait and delay your insulin dose.

You can take half of your meal or take some snacks and recheck your blood glucose after 30 minutes. If it’s above 100 and you are no more symptomatic, you can administer half of your insulin dose and complete your meal.

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Insulin therapy for travelers with type-2 diabetes

Stepping out of your comfort zone, your home, where you have everything available can be quite stressful.

When you are traveling there are chances of your blood sugar levels fluctuating. It is important to keep a close look at your blood glucose levels while traveling and keep all the essential items that you might need close to you.

On the day you are supposed to leave for your journey, take your regular insulin up to the time you are scheduled to leave, and then take short-acting insulin doses before the additional meals.

As a rough approximation, use 10% of your typical daily dosage; you can adjust it up or down based on your blood result.

Monitor your blood glucose levels constantly, in case of hypoglycemia eat some snacks.

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Insulin therapy during the perioperative period

The perioperative period is the time that surrounds a surgery, this includes both the post-operative time and the time immediately before the surgery (pre-operative).

Insulin must be administered intraoperatively to all type-1 diabetic patients and many type-2 diabetic patients to keep blood sugar levels under control.

If the surgery is relatively brief, patients with type 2 diabetes who are chronically managed solely through diet or low doses of oral medications and who are in good control before surgery may not need insulin.

Insulin therapy for type 2 diabetes is useful to maintain glycemic control in numerous circumstances, such as chronic poor control or difficult surgical operations.

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Insulin therapy during the perioperative period:

  • During the perioperative phase, it is important to keep blood glucose levels within a specific range, such as between 120 and 180 mg per dL [6.67 and 10 mmol per L].
  • The insulin infusion begins at a rate of 0.5 to 1 U per hour in a type-1 diabetic patient.
  • The beginning dose is often larger, averaging 2 to 3 U per hour or more, in patients with poor control or type 2 diabetes.
  • Based on hourly glucose measurements, a glucose feedback algorithm adjusts the infusion rate. [ref]

What do you think?

Written by Dr. Ahmed

I am Dr. Ahmed (MBBS; FCPS Medicine), an Internist and a practicing physician. I am in the medical field for over fifteen years working in one of the busiest hospitals and writing medical posts for over 5 years.

I love my family, my profession, my blog, nature, hiking, and simple life. Read more about me, my family, and my qualifications

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