Agents to Control Blood Glucose Levels

Diabetes Mellitus (DM)

Is a complicated disorder that alters the metabolism of glucose, fats, and proteins affecting many end organs & causing numerous clinical complications; Maintaining the serum level glucose within a certain range is very important to CNS

Diabetes Mellitus Type 1 (DMI)/Insulin Dependent Diabetes Mellitus (IDDM)

Lack of insulin production or production of defective insulin (autoimmune process); Affected patients need exogenous insulin to survive; Can lead to Diabetic Ketoacidosis (DKA)

Diabetes Mellitus Type 2 (DMII)/Non-Insulin Dependent Diabetes Mellitus (NIDDM)

Caused by insulin deficiency and/or insulin resistance; Can lead to Hyperosmolar Hyperglycemic Syndrome (HHS)

Gestational Diabetes Mellitus/Pregnancy-Induced Diabetes Mellitus

Hyperglycemia that develops during pregnancy

Treatments for Diabetes

T1DM: Insulin Therapy; T2DM: Lifestyle changes, oral medications, insulin medications if necessary; Gestational DM: oral and insulin medications

Glycemic Goal of Treatment

HbA1c <7%

Types of Antidiabetic Drugs

Insulins (injectable, pens, pumps, inhaled); Oral hypoglycemic drugs

Insulins

Effects are the same as normal endogenous insulin; Human insulin: derived using recombinant DNA technology (produced by bacteria and yeast); Given SC or Parentally (IV continuous infusion, IVP in emergencies); Insulin drugs are differentiated according to their onset of action; Can be used in combination with each other

Rapid-Acting Insulins

Most rapid onset of action (5-15 min); Peak: 1-2 hrs; Duration: 3-5 hrs; Patient must eat a meal after injection; Examples: Insulin lispro (Humalog), Insulin aspart (Novolog); canNOT be given IV

Short-Acting Insulins

Onset: 30-60 min; Peak: 2-4 hrs; Duration: 6-8 hrs; Examples: Regular insulin (Humulin R; looks clear); Routes of administration: IV bolus, IV infusion, IM, SC

Intermediate-Acting Insulins

Onset: 1-2 hrs; Peak: 4-8 hrs; Duration: 10-18 hrs; Examples: Neutral Protamine Hagedorn (NPH; looks cloudy)

Long-Acting Insulins

Onset: 1-2 hrs; Peak: NONE; Duration: 24 hrs; Examples: Insulin glargine (Lantus); Constant level of insulin in the body

Sliding-Scale Insulin Dosing

Rapid-Acting or Short-Acting insulins are adjusted according to blood glucose level; Used for meal-by-meal basis; Advantages: no accidental hypoglycemia, works well in settings where glucose can change quickly; Disadvantages: delays insulin administration until hyperglycemia occurs, results in large swings in glucose control

Basal-Bolus Insulin Dosing

Preferred method of treatment; Mimics a healthy pancreas by delivering basal insulin constantly as a basal and then as needed as a bolus

Basal insulin

Long-acting insulin (insulin glargine)

Bolus insulin

Rapid-acting insulin (insulin lispro or insulin aspart) or short-acting insulin (R)

Pharmacologic Therapy for T1DM

Most people with type 1 diabetes should be treated with multiple daily injections of prandial and basal insulin, or continuous subcutaneous insulin infusion; Most individuals with type 1 diabetes should use rapid-acting insulin analogs to reduce hypoglycemia risk; Patients with type 1 diabetes should be trained to match prandial insulin doses to carbohydrate intake, premeal blood glucose, and anticipated physical activity

Insulin Nursing Implications

Ensure Correct Route, Correct Type of Insulin, Timing of the Dose, Correct Dosage; Always check blood glucose level BEFORE giving insulin; Check to see if the patient is NPO; Always draw Regular or Rapid-Acting Insulin FIRST (Clear BEFORE Cloudy)

NPO Glucose Risks

Risk of Hypoglycemia; Disrupted Glucose Regulation (Pts eat food to maintain glucose levels); Medication Timing Issues (Pts need to food to prevent hypoglycemia or GI side effects); Stress Response Increases Glucose; Altered Insulin Needs (liver still releases glucose which requires altered insulin doses); Delayed Treatment or Procedures (Pt may become hypoglycemic and require IV dextrose)

Insulin Dosing and Syringes

U100: Standard for most (100 units/mL); U200-500: Insulin pens (for people SEVERELY insulin resistant)

Oral Antidiabetic Drugs (OADs)

Used for T2DM; Examples: Metformin; Insulin is the LAST RESORT

Metformin

First-line drug and is the most commonly used oral drug for the treatment of T2DM

Metformin Mechanism of Action

Does NOT cause hypoglycemia

Metformin Contraindications

Renal and liver dysfunction; Iodinated Contrast Administration can cause lactic acidosis

Metformin Adverse Effects

Primarily affects GI tract (abdx bloating, nausea, cramping, diarrhea, feeling of fullness which causes reduced appetite and anorexia); Lactic acidosis is rare but can be lethal if it occurs (muscle aches, abdx pain, rapid breathing)

Lactic Acidosis

The key signs of lactic acidosis include unusually deep and rapid breathing, muscle aches/cramps, and abdominal pain

Sulfonylureas

Examples: Glipizide (Glucotrol), Glyburide (DiaBeta)

Sulfonylureas Contraindications

Renal and liver dysfunction

Sulfonylureas Adverse Effects

Hypoglycemia (Must take within 30 minutes of meals); GI Effects: nausea, vomiting, heartburn, weight gain

Meglitinides

Examples: Repaglinide (Prandin)

Thiazolidinediones (Glitazones)

Examples: Pioglitazone (Actos)

Thiazolidinediones (Glitazones) Adverse Effects

Black Box Warning for increased risk of heart failure

Thiazolidinediones (Glitazones) Contraindications

Patients with Heart Failure

Sodium-Glucose Co-Transporter 2 (SGLT2) Inhibitors

Examples: Empagliflozin (Jardiance)

Sodium-Glucose Co-Transporter 2 (SGLT2) Inhibitors Adverse Effects

Hypovolemia, hypotension, and glycosuria can facilitate genital fungal infection and UTI

Alpha-Glucosidase Inhibitors

Examples: Acarbose (Precose); Must take with the first bite of a meal

Dipeptidyl Peptidase-IV (DPP-4) Inhibitors

Examples: Sitagliptin (Januvia)

Glucagon-Like Peptide-1 (GLP)-1 Receptor Agonists

Examples: Semaglutide (Ozempic), Tirzepatide (Mounjaro)

Glucagon-Like Peptide-1 (GLP)-1 Receptor Agonists Adverse Effects

Weight loss; GI effects (nausea, vomiting, diarrhea, gastroparesis); HYPOGLYCEMIA; Injection site reactions

Tirzepatide (Mounjaro, Zepbound)

Mounjaro: brand name used when prescribing for T2DM; Zepbound: brand name approved for weight loss/chronic weight management/obstructive sleep apnea; First dual GIP/GLP-1 receptor agonist (harnesses both GIP and GLP-1 pathways)

Tirzepatide on GIP Pathway

Further enhance insulin secretion and may boost weight loss through additional metabolic pathways

Tirzepatide on GLP-1 Pathway

Lowers blood glucose, slows gastric emptying, reduces appetite

Glucagon-Like Peptide-1 (GLP-1)

A hormone released from L-cells in the distal small intestine and colon in response to food intake.

Stimulates insulin secretion and suppresses glucagon release (both glucose-dependent). Slows gastric emptying → helps control postprandial glucose spikes. Increases satiety and reduces appetite via effects on the brain.

Glucose-Dependent Insulinotropic Polypeptide (GIP)

A hormone secreted by the K-cells of the small intestine after eating

Stimulates insulin release from pancreatic beta cells in a glucose-dependent manner (more effective when blood glucose is elevated). Plays a role in fat metabolism by promoting lipid storage in adipose tissue.

By itself, GIP has a limited effect on lowering glucose in people with type 2 diabetes (because the body’s response to GIP is often blunted)

Different Forms of Semaglutide

Ozempic: for T2DM; Wegovy: for obesity; Rybelsus: for T2DM

Hypoglycemia

Abnormally Low Blood Glucose Level: < 50 mg/dL; Early S/S: confusion, irritability, hunger, restlessness, tremor, sweating, tachycardia; Late S/S: hypothermia, seizures; Mild cases can be treated with diet (higher intake of protein and lower intake of carbs to prevent hyperglycemia)

Glucose-Elevating Drugs

Oral forms of concentrated glucose (buccal tablets, semisolid gel, juices; must be conscious to take); IV 50% dextrose in water (D50W); Glucagon (IV, SC, IM)

Hypoglycemia Nursing Implications

Administer oral form of glucose if the patient is CONSCIOUS; Deliver D50W or Glucagon IV if patient is UNCONSCIOUS

Pharmacologic Therapy for T2DM

Patient-centered approach: cardiovascular comorbidities, hypoglycemia risk, impact on weight, cost, risk for side effects, and patient preferences

Metformin is the preferred initial agent to max dose of 2,550 mg/day

In patients who need greater glucose lowering than can be obtained with oral agents, glucagon-like peptide-1(GLP-1) receptor agonists are preferred over insulin when possible

The medication regimen and medication-taking behavior should be reevaluated at regular intervals (every 3–6 months)

All Antidiabetic Drugs Nursing Implications

Before giving drugs that alter glucose levels, obtain and document:

• A thorough past medical & history (PMH)

• Alcohol intake

• Vital signs

• Family history

• Dietary lifestyle

• Blood glucose level, HbA1C level

• Potential complications and drug interactions

• Allergies

• Educational level & ability to learn

Hypoglycemia may be a problem if antidiabetic drugs are given, and the patient does not eat

If a patient is NPO for a test or procedure, consult the primary care provider to clarify orders for antidiabetic drug therapy

Keep in mind that overall concerns for any patient with DM increase when the patient:

• Is under stress

• Has an infection

• Has an illness or trauma

• Is pregnant or lactating

• Certain medications