Human Insulin/Soluble Insulin

Usage

• Human insulin/soluble insulin is prescribed for the treatment of type 1 and type 2 diabetes mellitus. It is also used to manage hyperglycemia (high blood sugar) and diabetic ketoacidosis (DKA). In some cases, it’s used during surgical procedures or in intensive care settings.
• Pharmacological Classification: Rapid-acting insulin, antidiabetic agent.
• Mechanism of Action: Mimics the action of endogenous insulin, facilitating glucose uptake by cells in muscle, liver, and adipose tissue, thereby lowering blood glucose levels.

Alternate Names

• Regular insulin, neutral insulin, soluble insulin
• Brand Names: Actrapid, Humulin R, Novolin R, others.

How It Works

• Pharmacodynamics: Lowers blood glucose by promoting glucose uptake into cells and inhibiting hepatic glucose production. It also affects fat and protein metabolism.
• Pharmacokinetics:
  • Absorption: Rapidly absorbed following subcutaneous injection, with peak action within 1-3 hours. Intravenous administration results in immediate action.
  • Metabolism: Primarily metabolized in the liver and kidneys.
  • Elimination: Excreted primarily through the kidneys.
• Mode of Action: Binds to insulin receptors on cell surfaces, triggering a cascade of intracellular events leading to increased glucose transport into cells via GLUT4 transporters.
• Receptor Binding: Binds to insulin receptors.
• Elimination Pathways: Primarily renal excretion.

Dosage

Standard Dosage

Adults:

• Type 1 Diabetes: 0.5-1 unit/kg/day subcutaneously, divided into multiple doses.
• Type 2 Diabetes: Starting dose: 0.1-0.2 unit/kg/day or 10 units/day subcutaneously, usually given in the evening or divided twice daily. Titrate upwards based on blood glucose levels.

Children:

• Dose is individualized based on the child’s weight, age, and metabolic needs, typically starting at 0.2-0.4 units/kg/day, divided into multiple doses. Pediatric endocrinologist consultation recommended.

Special Cases:

• Elderly Patients: May require lower doses due to age-related decline in renal function and insulin sensitivity.
• Patients with Renal Impairment: Dose reduction may be necessary depending on the degree of renal impairment.
• Patients with Hepatic Dysfunction: Dose adjustments may be necessary.
• Patients with Comorbid Conditions: Dosage adjustments may be necessary based on other medical conditions.

Clinical Use Cases:

• Intubation/Surgical Procedures/Mechanical Ventilation/ICU Use: Continuous IV infusion at 0.1 unit/kg/hour is commonly used, titrated to maintain desired blood glucose levels.
• Emergency Situations (e.g., DKA): 0.1 unit/kg IV bolus followed by 0.1 unit/kg/hour continuous IV infusion. Alternatively, 0.14 unit/kg/hour IV infusion without bolus can be administered. Blood glucose levels must be closely monitored, and dose adjusted accordingly. When blood glucose is <250 mg/dL, switch to glucose-containing fluids orally and reduce insulin to 0.05 unit/kg subcutaneously.

Dosage Adjustments:

• Renal/hepatic dysfunction: Reduce dose based on individual patient’s clearance.
• Metabolic disorders: Adjust dose based on specific metabolic needs.

Side Effects

Common Side Effects:

• Hypoglycemia (low blood sugar), weight gain, injection site reactions (redness, swelling, itching).

Rare but Serious Side Effects:

• Severe hypoglycemia (loss of consciousness, seizures), allergic reactions (rash, hives, difficulty breathing).

Long-Term Effects:

• Lipodystrophy (changes in fat tissue at injection site) with repeated injections at the same site.

Adverse Drug Reactions (ADR):

• Anaphylaxis (severe allergic reaction).

Contraindications

• Hypoglycemia.
• Hypersensitivity to insulin or any component of the formulation.

Drug Interactions

• Medications that can affect blood sugar levels (e.g., corticosteroids, beta-blockers, thiazide diuretics).
• Alcohol can increase the risk of hypoglycemia.
• Beta-blockers can mask the symptoms of hypoglycemia.

Pregnancy and Breastfeeding

• Pregnancy Safety Category: Generally considered safe during pregnancy. Blood glucose monitoring is crucial. Insulin requirements may change during pregnancy.
• Breastfeeding: Insulin is not likely to be excreted in breast milk in significant amounts. Dosage adjustments may be necessary during breastfeeding.

Drug Profile Summary

• Mechanism of Action: Facilitates glucose uptake by cells, lowering blood glucose.
• Side Effects: Hypoglycemia, weight gain, injection site reactions.
• Contraindications: Hypoglycemia, hypersensitivity.
• Drug Interactions: Corticosteroids, beta-blockers, thiazide diuretics, alcohol.
• Pregnancy & Breastfeeding: Generally safe, monitor blood glucose, may require dosage adjustments.
• Dosage: Individualized, starting at 0.2-0.4 unit/kg/day for type 1 diabetes, 0.1-0.2 unit/kg/day for type 2 diabetes.
• Monitoring Parameters: Blood glucose levels, HbA1c.

Popular Combinations

• Often combined with intermediate- or long-acting insulins (e.g., NPH insulin, glargine) to provide both basal and bolus insulin coverage.

Precautions

• General Precautions: Monitor blood glucose regularly. Rotate injection sites.
• Specific Populations: Dosage adjustments as needed for pregnant/breastfeeding women, children, and the elderly.
• Lifestyle Considerations: Diet and exercise play a significant role in managing diabetes.

FAQs (Frequently Asked Questions)

Q1: What is the recommended dosage for Human Insulin/Soluble Insulin?

A: Highly individualized, but generally 0.5-1 unit/kg/day for type 1 and 0.1-0.2 unit/kg/day or 10 units/day for type 2, divided into multiple doses.

Q2: How should Human Insulin be administered?

A: Subcutaneously, usually before meals. Can be given intravenously in hospital settings.

Q3: What are the signs and symptoms of hypoglycemia?

A: Sweating, trembling, dizziness, confusion, hunger, headache, and in severe cases, loss of consciousness and seizures.

Q4: What should a patient do if they experience hypoglycemia?

A: Consume a fast-acting carbohydrate (e.g., glucose tablets, juice, candy) and recheck blood sugar after 15 minutes. If symptoms persist, seek medical attention.

Q5: Can Human Insulin be used during pregnancy?

A: Yes, it is generally considered safe, but close blood glucose monitoring and dosage adjustments may be necessary.

Q6: What are the long-term complications of poorly controlled diabetes?

A: Cardiovascular disease, nephropathy, neuropathy, retinopathy, and foot problems.

Q7: How often should a patient on Human Insulin monitor their blood glucose?

A: Frequency depends on individual needs and diabetes management plan, but usually multiple times per day.

Q8: What are the potential drug interactions with Human Insulin?

A: Corticosteroids, beta-blockers, thiazide diuretics, and alcohol.

Q9: What is the role of diet and exercise in managing diabetes with Human Insulin?

A: Diet and exercise are essential components of diabetes management, along with insulin therapy, to maintain optimal blood glucose control and overall health.

Q10: What are the storage requirements for Human Insulin?

A: Unopened vials should be refrigerated. In-use vials can be stored at room temperature for up to 28 days. Do not freeze.