Unit 8: The Endocrine System

Chapter 44: Drugs for Diabetes Mellitus

Pancreas

Describe the secretory function of the pancreas.

Which pancreatic cells are essential to the endocrine function?

Why is the endocrine function of the pancreas so important?

Insulin

• Secretion regulated by chemical, hormonal, and neural factors

• Key to metabolic process in most body cells • Transport vehicle for glucose (except brain)

Why does glucose not need a transport vehicle into brain cells?

• What is the most important regulator of insulin secretion? (Think about the negative feedback loop)

Contributors to Glucose Homeostasis

Hyperglycemic effects• Hormones

– Epinephrine– Thyroid hormone– Growth hormone– conticosteroids

• Drugs– Phenytoin– NSAIDs– Diuretics– Steroids

Hypoglycemic effects • Drugs

– Alcohol– Lithium– ACE Inhibitors– Beta-adrenergic blockers

Diabetes Mellitus

• Chronic metabolic disorder characterized by hyperglycemia

• Etiology: combination of genetic and environmental factors

• Increasing incidence• Group of disorders caused by:– Deficient to absent insulin secretion– Decreased insulin receptor sensitivity

Type I Diabetes Mellitus

• Usually presents during childhood• Aka: insulin dependent diabetes mellitus• Etiology: – autoimmune destruction of pancreatic beta cells– Interaction of genetic, immunologic, and

environmental factors• Consistent presenting signs/symptoms– Hyperglycemia, polyuria, polyphagia, polydipsia,

glycosuria, weight loss, fatigue

Potential Complications

• Arterial damage• Altered peripheral circulation• Nerve degeneration• Impaired lipid metabolism

Pharmacotherapy for Type I Diabetes Mellitus

• What are the current options for Insulin therapy?

• What is the therapeutic goal and desired outcome of insulin therapy?

• What additional measures are used with insulin pharmacotherapy to control Type 1 DM?

Insulin Therapy

Fundamental Principle:“the right amount of insulin must be available to

cells when glucose is available in the blood.”

What is the consequence of administering insulin when glucose is not available?

What is the consequence of forgetting or skipping scheduled insulin dosage?

Insulin Therapy

• What is the primary adverse effect of insulin therapy?

• Other adverse effects include:– Localized allergic reaction – Generalized urticaria– Swollen lymph glands

Hypoglycemia (Insulin Reaction)

• Symptoms occur when there is more insulin in the blood than needed.

• Causes:– Insulin levels peak during exercise– Received too much insulin– Skipped meal after taking dose of insulin

• May be treated with glucagon – Can cause response in ≤ 20 min

Somogyi Phenomenon

• Rapid decrease in blood glucose (typically at night)

• Stimulates release of hormones that increase blood glucose

• Morning blood glucose is elevated

Types of Insulin

• Most insulin given today is human insulin • Human insulin has been modified to produce

a more rapid onset or longer duration. (Insulin Analogs)

• Classified as rapid, short, intermediate, or long acting

Nursing Considerations

• What are nursing considerations for insulin therapy?• What must the nurse be familiar

with? • What teaching must be included?

Type 2 Diabetes Mellitus

• Major type of diabetes mellitus• Endogenous insulin present in deficient

amounts• Fundamental problem– Insulin resistance

• Poor management results in same complications as Type 1 diabetes mellitus

• Recommendation: preprandial glucose < 110 mg/dl

Oral Hypoglycemics

• Lower blood sugar• Some may cause hypoglycemia• Classified based on structure and mechanism

of action• Initially monotherapy• Insulin may need to be added to regimin• Some combination drugs are available. Why?

Classes of Hypoglycemic Agents

• Sulfonylureas• Biguanides• Alpha-glucosidase Inhibitors • Thiazolidinediones• Meglitinides • New drugs

Develop a table to compare and contrast

Incretin-Glucose Control Mechanism

• Incretin is a hormone secreted by the intestines in response to a meal when blood glucose is elevated.

• Increased incretin levels signals the pancreas to increase insulin secretion and the liver to stop producing glucagon.

Why is this important?

exenatide (Byetta)

• Mimics the action of incretin• Causes increased secretion of insulin, slows

absorption of glucose, and reduces action of glucagon

• Subcutaneously 1-2 times per day• Adverse effects:– Significant nausea, vomiting, diarrhea

Additional New Drugs

• Dipeptidyl peptidase – 4 (DPP4) Inhibitors– Sitagliptin phosphate (Januvia)– Inhibits destruction of incretin

• pramlinitide (Symlin)– Resembles pancreatic hormone amylin– Assists with glucose regulation• Slows absorption of glucose• Inhibits action of glucagon

Nursing Considerations

• What are the nursing considerations for hypoglycemic agents?• What needs to be included in

teaching?