CH 50 PHARM

Chapter 50: Antidiabetics

Overview of Diabetes Mellitus

• Chronic Disease Mechanisms

  • Results from deficient glucose metabolism

  • Causes include:

    • Insufficient insulin secretion from beta cells

    • Insulin resistance

  • Insulin receptors can be unresponsive or deficient in numbers

Major Symptoms of Diabetes Mellitus

• Symptoms to monitor:

  • Polyuria: Increased urination

  • Polydipsia: Increased thirst

  • Polyphagia: Increased hunger

Types of Diabetes Mellitus

• Type 1: Insulin-dependent DM

• Type 2: Non-insulin-dependent DM

• Secondary Diabetes:

  • Due to medications such as glucocorticoids, thiazide diuretics, epinephrine

• Gestational Diabetes:

  • Occurs due to hormonal changes during pregnancy

Insulin Overview

• Insulin Function:

  • Released from beta cells of the islets of Langerhans in pancreas

  • Secreted in response to increases in blood glucose

  • Promotes uptake of glucose, amino acids, and fatty acids

  • Converts glucose to glycogen in liver and muscle for future needs

• Normal Blood Glucose Range:

  • Monitor Hemoglobin A1C levels

Types of Insulin

• Manufactured Insulin:

  • Derived using DNA technology (examples: Humulin R, Novolin N)

  • Lower incidence of allergies and resistance to insulin

• Types of Insulin:

  • Rapid-acting: Insulin lispro, aspart, glulisine

  • Short-acting: Regular insulin

  • Intermediate-acting: Insulin isophane NPH

  • Long-acting: Insulin glargine

  • Combinations: Short & intermediate-acting or rapid & intermediate-acting (e.g., NPH 70/Regular 30)

Insulin Resistance and Storage

• Insulin Resistance:

  • Development of antibodies to animal insulin over time

  • Obesity can cause insulin resistance

• Storage:

  • Refrigerate insulin until opened

  • Avoid sunlight and high temperatures

Actions of Insulin

• Promotes glucose uptake by body cells and stores glucose as glycogen

• Interventions for Blood Glucose Management:

  • Monitor blood glucose

  • Adjust medications based on glucose levels

  • Monitor how certain drugs can increase or decrease glucose levels

Sliding Scale Insulin

• Sliding-scale Insulin Coverage:

  • Adjust doses based on individual blood glucose

  • Requires monitoring before meals and at bedtime

Insulin Side Effects

• Hypoglycemia:

  • Symptoms include trembling, lack of coordination, sweating, tachycardia, headache, and confusion

• Somogyi Effect:

  • Response to excess insulin causing rapid decrease in blood glucose, stimulating hormonal releases to increase blood glucose

• Dawn Phenomenon:

  • Elevated blood glucose upon waking, may include headaches and night sweats

• Lipodystrophy:

  • includes lipohypertrophy and lipoatrophy

Diabetic Ketoacidosis

• Manifestation of Insulin Deficiency:

  • Hyperglycemia leads to water loss, hemoconcentration, altered fat metabolism, and production of ketoacids

  • Can result in acidosis, coma, and death

Insulin Administration Methods

• Methods:

  • Insulin pen injectors, insulin pumps, insulin jet injectors

Assessment and Interventions

• Monitor blood glucose levels and HbA1C

• Teach patients to recognize symptoms of hypoglycemia and hyperglycemia

• Provide education on insulin administration and dietary adherence

Oral Antidiabetic Drugs

• Sulfonylureas:

  • Include tolbutamide, tolazamide, chlorpropamide, glimepiride, and glipizide

  • Actions include stimulating pancreatic beta cells, increasing tissue response to insulin, and decreasing glucose production

  • Side effects: hypoglycemia, blurred vision, nausea, diarrhea

Biguanides: Metformin

• Action:

  • Decrease hepatic glucose production, diminish glucose increase post-meal, and increase insulin receptor sensitivity

Alpha-Glucosidase Inhibitors

• Acarbose & Miglitol:

  • Inhibit digestive enzymes in the small intestine to prevent glucose release from carbohydrates

Thiazolidinediones

• Pioglitazone & Rosiglitazone:

  • Decrease insulin resistance; side effects include headache, dizziness, edema, and contraindications in heart failure

Meglitinides

• Repaglinide & Netaglinide:

  • Stimulate short-acting beta cell insulin release; watch for hypoglycemia

  • Contraindications: liver dysfunction

Incretin Modifiers

• Gliptins (e.g. Januvia):

  • Increase incretin hormones to boost insulin secretion; used alongside diet and exercise

GLP Agonists

• Exenatide & Liraglutide:

  • Enhance insulin secretion, suppress glucagon secretion, slow gastric emptying

Amylin Analogues

• Action:

  • Suppress glucagon, slow gastric emptying, induce satiety

• Common side effects include dizziness, nausea, abdominal pain

Criteria for Use of Oral Antidiabetic Drugs

• Onset at age 40 or older

• Diabetes diagnosis for less than 5 years

• Normal weight or overweight

• Fasting blood glucose of 200 mg/dL or less

• Need for less than 40 units of insulin/day

Assessment for Oral Antidiabetics

• Administer with food to minimize gastric upset

• Monitor blood glucose levels

• Educate on recognizing symptoms of hyperglycemia/hypoglycemia

Hyperglycemics

• Glucagon:

  • Increases blood glucose by stimulating glycogenolysis

• Diazoxide:

  • Increases blood glucose by inhibiting insulin release

Practice Questions

• Examples of clinical situations involving insulin administration, patient education, and recognition of potential side effects.