Antidiabetic medications are drugs used to control elevated blood glucose levels in diabetes mellitus. Among all antidiabetics, insulin is the most essential therapy, especially for Type 1 diabetes and advanced Type 2 diabetes.
This article explains insulin uses, mechanism, adverse effects, and types of insulin with onset, peak, and duration.
What Are Antidiabetics?
Antidiabetics are medications used to decrease high blood sugar levels.
They include:
- Insulin preparations
- Oral antidiabetic drugs (Metformin, Sulfonylureas, SGLT2 inhibitors, etc.)
- Injectable non-insulin drugs (GLP-1 agonists)
This article focuses only on Insulin.
Insulin
Class:
P: Insulins
T: Antidiabetics
Uses:
Reduces blood sugar levels in diabetic patients.
Mechanism of Action (MOA):
Insulin stimulates the cellular uptake of glucose, lowers blood glucose levels, and converts excess glucose into glycogen for energy storage.
Adverse Effects:
Remember the H’s:
- Hypoglycemia
- Hypokalemia
- Headache
- Hives
Types of Insulin
Insulin types are classified based on onset, peak, and duration of action.
Rapid-Acting Insulin
Examples: Aspart, Lispro, Glulisine
Onset: 15 minutes
Peak: 30 minutes
Duration: 3 hours
Given with meals.
Mnemonic: E’s
- Eat with injection
- Effective immediately
- Eliminates a LAG (Lispro, Aspart, Glulisine)
Short-Acting Insulin
Example: Regular Insulin
Onset: 1 hour
Peak: 2 hours
Duration: 4 hours
Given with meals.
Mnemonic: R’s
- Run IV
- Regular
- Rapid (but slower than rapid-acting)
Only insulin that can be given IV (used in DKA).
Intermediate-Acting Insulin
Example: NPH
Onset: 6 hours
Peak: 8 hours
Duration: 12 hours
Appears cloudy.
Mnemonic: N’s
- NPH
- Not fast
- Not clear
- Non-compliant patients (usually twice daily)
Long-Acting Insulin
Examples: Glargine (Lantus), Detemir, Degludec
Onset: Variable
Peak: None
Duration: 12–24 hours
Given 1–2 times per day.
Mnemonic: L’s
- Lantus
- Lasts 24 hours
- Lack of peak
Summary Table of Insulin Types
| Type | Example | Onset | Peak | Duration | Key Notes |
|---|---|---|---|---|---|
| Rapid | Lispro, Aspart | 15 min | 30 min | 3 hrs | With meals |
| Short | Regular | 1 hr | 2 hrs | 4 hrs | Only IV insulin |
| Intermediate | NPH | 6 hrs | 8 hrs | 12 hrs | Cloudy |
| Long | Glargine | — | No peak | 12–24 hrs | Basal control |
Clinical Uses of Insulin
- Type 1 diabetes (mandatory)
- Type 2 diabetes (when oral drugs fail)
- Diabetic ketoacidosis (Regular insulin IV)
- Hyperkalemia (insulin + glucose shifts potassium into cells)
- Gestational diabetes
- Perioperative glycemic control
Nursing Considerations
- Check blood glucose before administration.
- Rotate injection sites to prevent lipodystrophy.
- Do not mix long-acting insulin (Glargine) with other insulins.
- Ensure food intake after rapid/short-acting insulin.
- Roll NPH vial gently; do not shake.
- Keep glucagon available for severe hypoglycemia.
Signs of Hypoglycemia
- Sweating
- Tremors
- Rapid heart rate
- Hunger
- Confusion
- Drowsiness
Importance of Understanding Insulin
For students, understanding insulin pharmacology is essential for exams, clinical postings, drug calculations, safe nursing practice, and patient care.
