Hypoglycemic agents are drugs used to lower high blood glucose levels, mainly in the treatment of diabetes mellitus—especially Type 1 and Type 2 diabetes. These drugs include insulin (parenteral) and several classes of oral antidiabetic agents.
What Is Diabetes Mellitus?
Diabetes is a chronic metabolic disorder marked by high blood glucose due to either:
- Insufficient insulin secretion (Type 1)
- Insulin resistance or reduced insulin action (Type 2)
Classification of Hypoglycemic Agents
They are broadly divided into:
- Insulin and insulin analogues
- Oral hypoglycemic agents
1. Insulin and Its Preparations
Insulin is a peptide hormone produced by pancreatic β-cells. It regulates carbohydrate and fat metabolism by promoting glucose uptake into tissues.
Types of Insulin Preparations
- Rapid-acting: Insulin lispro, aspart
- Short-acting: Regular insulin
- Intermediate-acting: NPH insulin
- Long-acting: Insulin glargine, detemir
Mechanism of Action
- Promotes glucose uptake by muscle and fat cells
- Decreases hepatic glucose production
- Promotes glycogen formation
- Increases protein synthesis
Uses
- Type 1 diabetes (mandatory)
- Type 2 diabetes (when oral drugs fail)
- Diabetic ketoacidosis
2. Oral Hypoglycemic Agents
2.1 Sulfonylureas
These drugs stimulate insulin release from the pancreas.
Mechanism
They block ATP-sensitive K⁺ channels in β-cells → membrane depolarization → Ca²⁺ entry → insulin release.
Examples
- Tolbutamide
- Chlorpropamide
- Glibenclamide
- Glipizide
2.2 Biguanides
The most important drug is Metformin.
Mechanism
- Decreases hepatic glucose production
- Increases insulin sensitivity
- Enhances glucose uptake
Uses
First-line therapy for Type 2 diabetes.
2.3 Thiazolidinediones (TZDs)
Also known as insulin sensitizers.
Examples
- Pioglitazone
- Rosiglitazone
Mechanism
Activate PPAR-γ → improve insulin sensitivity in adipose tissue and muscle.
2.4 Alpha-Glucosidase Inhibitors
Delay carbohydrate digestion and glucose absorption.
Examples
- Acarbose
- Miglitol
2.5 Meglitinides
Short-acting insulin secretagogues.
Examples
- Repaglinide
- Nateglinide
2.6 DPP-4 Inhibitors (Gliptins)
Increase incretin hormones (GLP-1, GIP) which stimulate insulin release.
Examples
- Sitagliptin
- Vildagliptin
- Saxagliptin
2.7 SGLT-2 Inhibitors
Increase urinary glucose excretion by blocking glucose reabsorption in kidneys.
Examples
- Canagliflozin
- Dapagliflozin
- Empagliflozin
Side Effects
- Insulin: Hypoglycemia, weight gain
- Sulfonylureas: Hypoglycemia, weight gain
- Metformin: GI upset, lactic acidosis (rare)
- TZDs: Weight gain, edema
- Acarbose: Flatulence, abdominal discomfort
Combination Therapy
For better control of Type 2 diabetes, drugs from different classes are often combined—for example:
- Metformin + Sulfonylurea
- Metformin + DPP-4 inhibitor
- Metformin + SGLT-2 inhibitor
Detailed Notes:
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