Drugs for Diabetes Mellitus

Overview of Diabetes Mellitus

  • Definition: A disorder of carbohydrate metabolism due to:
    • Deficiency of insulin or
    • Resistance to the action of insulin
  • Types:
    • Type 1
    • Type 2
    • Prediabetes
    • Gestational Diabetes
  • Short term complications:
    • Hypoglycemia (Low blood sugar):
    • Symptoms: Tachycardia, fatigue, sweating, pallor (cool and clammy)
    • Urgency when patients show signs; difficult to arouse, may lose consciousness
    • Hyperglycemia (High blood sugar):
    • Symptoms: Polyuria (excessive urination), polydipsia (excessive thirst)
    • Ketoacidosis:
    • Severe and persistent hyperglycemia, production of ketoacids, hemoconcentration, acidosis, and coma
    • Symptoms: Rotten smelling urine, "juicy fruit breath" (common in Type 1), requires close monitoring of blood sugar due to life-threatening nature
  • Long term complications:
    • Macrovascular damage:
    • Heart disease
    • Hypertension
    • Stroke
    • Microvascular damage:
    • Retinopathy (potential blindness)
    • Nephropathy (kidney damage)
    • Neuropathies:
      • Sensory & motor neuropathy (numbness, tingling in feet)
      • Autonomic neuropathy (gastroparesis—a delayed stomach emptying)
    • Potential complications: amputations, erectile dysfunction

Types of Diabetes Mellitus

Type 1 Diabetes
  • Age of Onset: Usually in childhood/adolescence
  • Speed of Onset: Abrupt
  • Family History: Frequently negative
  • Prevalence: 5% of all diabetes cases
  • Etiology: Autoimmune process leading to loss of pancreatic beta cells
  • Insulin Levels: Reduced early, completely absent later
  • Treatment: Mandatory insulin replacement with strict dietary control
  • Symptoms: Polyuria, polydipsia, polyphagia, weight loss; patients usually thin and undernourished at diagnosis
  • Ketosis: Common, especially with insufficient insulin dosage
Type 2 Diabetes
  • Age of Onset: Usually over 40 years
  • Speed of Onset: Gradual
  • Family History: Frequently positive
  • Prevalence: 90%-95% of diabetes cases
  • Etiology: Unknown; strong familial association suggests heredity risk
  • Primary Defect: Insulin resistance and inappropriate insulin secretion
  • Insulin Levels: Can be low, normal, or high
  • Treatment: Use oral antidiabetics or non-insulin injectables alongside insulin when necessary, combined with a reduced-calorie diet and exercise
  • Symptoms: Usually obese; may be asymptomatic initially
  • Ketosis: Uncommon

Overview of Diabetes Treatment

  • Primary Goal: Prevention of long-term complications
  • Blood Glucose Control:
    • Tight control is essential
    • Monitoring blood pressure and lipids also critical
  • Optimal Control: Reduces long-term complications relating to eyes, kidneys, and nerve damage
Monitoring Blood Glucose
  • Self-Monitoring of Blood Glucose (SMBG):
    • Insulin Patients: Checked multiple times daily
    • Type 2 Oral Medication Patients: Checked weekly
  • Common Target Values:
    • 80 to 130 mg/dL before meals
    • Less than 180 mg/dL after meals (1-2 hours)
    • 100 to 140 mg/dL at bedtime
Hemoglobin A1c
  • Also called glycosylated or glycated hemoglobin
  • Purpose: Provides average glucose levels over the prior 2-3 months
  • Goal:
    • Below 7% is acceptable for most patients
    • Below 8% may be appropriate for those with severe hypoglycemia history, limited life expectancy, or advanced complications
Testing Methods
  1. Oral Glucose Tolerance Test:
    • Oral glucose load (75 g) followed by plasma glucose level measurement after 2 hours
    • A level of 200 mg/dL or higher suggests diabetes
  2. Random Plasma Glucose Test:
    • Blood drawn at any time; 200 mg/dL or higher suggests diabetes
  3. Fasting Plasma Glucose Test:
    • Blood drawn after 8 hours of fasting
    • 126 mg/dL or higher indicates diabetes

Drugs for Diabetes

Insulins
  • Types of Insulin:
    • Rapid-Acting Insulins:
    • Insulin lispro [Humalog]
    • Insulin aspart [NovoLog]
    • Slower-Acting Insulin:
    • Regular insulin [Humulin R, Novolin R]
    • Intermediate Duration:
    • NPH insulin
    • Long Duration:
    • Insulin glargine [Lantus]
    • Insulin detemir [Levemir]
Characteristics of Different Insulins
  1. Insulin lispro [Humalog]:
    • Onset: 15-30 minutes; to be given immediately before meals
    • Peak: 0.5-2.5 hours
    • Duration: 3-6 hours
  2. Insulin aspart [NovoLog]:
    • Onset: 10-20 minutes; given before meals
    • Peak: 1-3 hours
    • Duration: 3-6 hours
  3. Regular insulin [Humulin R, Novolin R]:
    • Onset: 30-60 minutes; to be given 30 mins before meals
    • Peak: 1-5 hours
    • Duration: Up to 10 hours
  4. NPH insulin [Humulin N, Novolin N]:
    • Onset: 60-120 minutes
    • Peak: 6-14 hours; at risk for hypoglycemia
    • Duration: 16-24 hours
  5. Insulin glargine [Lantus]:
    • Onset: 360 minutes
    • Peak: None
    • Duration: More than 24 hours; administered only once a day
  6. Insulin detemir [Levemir]:
    • Onset: 60-120 minutes
    • Peak: None
    • Duration: Greater than 24 hours
Insulin Administration
  • Methods:
    • Subcutaneous injection using syringes, pen injectors, jet injectors
    • Subcutaneous infusion with portable pumps
    • Intravenous infusion (for emergencies)
    • Inhalation (not commonly used)
  • Storage:
    • Unopened vials: Refrigeration needed
    • Should not be frozen; discard if frozen
    • After opening, can be kept for 1 month without loss of activity
    • Keep out of direct sunlight/heat
Insulin Dosage Schedules
  1. Twice Daily Premixed Insulin Regimen:
    • One short-acting and one long-acting shot per day
  2. Intensive Basal/Bolus Strategy:
    • Long-acting shot before bed and short-acting at each meal; daily blood sugar monitoring
  3. Continuous Subcutaneous Insulin:
    • Insulin pump manages administration as needed

Complications of Insulin Treatment

  • Hypoglycemia: Blood glucose below 70 mg/dL
  • Drug Interactions:
    • Risk of hypoglycemia—rapid treatment needed
    • Conscious patients: Give fast-acting oral sugar (e.g., orange juice, glucose tablets)
    • Unconscious patients: IV glucose or glucagon preferred; nothing orally
  • Lipohypertrophy:
    • Accumulation of subcutaneous fat due to frequent injections in the same site requires rotation
  • Other Side Effects: Allergic reactions, hypokalemia, interactions with alcohol, beta-adrenergic blockers, hyperglycemic agents
Oral Medications for Type 2 Diabetes
  • Biguanides:
    • Metformin: Decreases liver glucose production, increases tissue response; side effects include GI disturbances, rare lactic acidosis.
    • Pharmacokinetics: Daily oral; not metabolized, excreted by kidneys; interacts with alcohol, cimetidine, and radiocontrast media
  • Sulfonylureas:
    • Glipizide: Promotes insulin secretion; side effects include hypoglycemia, weight gain, administer with breakfast
    • Pharmacokinetics: Oral, half-life of 1 hour; metabolized in liver, excreted in urine & feces
  • Meglitinides:
    • Repaglinide, Nateglinide: Similar to Sulfonylureas but shorter acting; taken 30 mins before meals
  • Thiazolidinediones:
    • Pioglitazone: Used with metformin, works to reduce insulin resistance; side effects include hypoglycemia in the presence of excessive insulin, heart failure risks, bladder cancer
  • Alpha-glucosidase Inhibitors:
    • Acarbose, Miglitol: Delay absorption of carbohydrates
  • DPP-4 Inhibitors:
    • Sitagliptin: Enhance incretin activity, side effects include pancreatitis, assess for abdominal pain
  • SGLT-2 Inhibitors:
    • Canagliflozin: Prevent glucose reabsorption in kidneys, side effects include genital fungal infections, orthostasis
  • GLP-1 Receptor Agonists:
    • Exenatide: Lower blood glucose by stimulating insulin release, slow gastric emptying; once-weekly injection, associated with pancreatitis complications

Note: This document captures the essential details and systematic organization of relevant information regarding drugs for Diabetes Mellitus, ensuring comprehensive knowledge applicable for nursing and medical education.