Comprehensive Study Notes: Agents to Control Blood Glucose Levels

Insulin

  • Insulin is delivered using an ORANGE cap insulin syringe; this color coding is essential for safety.
  • Analogy: Insulin is the key that opens the door to cells to let glucose enter.
  • Indications and Uses
    • Diabetes mellitus Type I and Type II (Type I always uses insulin)
    • Hyperkalemia
    • Gestational diabetes
    • Times of stress (surgery or disease) may require insulin management
  • Administration basics
    • Ordered as “units” only
    • Typical vial concentration: 100 units/mL100\ \text{units/mL}
    • Administered via subcutaneous (subq) injection
    • May use an insulin pump (Regular insulin only) for continuous delivery
    • ONLY Regular insulin can be given via IV route
    • Cannot be given orally
    • Multidose vials are common
  • Insulin types (overview)
    • Rapid-acting insulins (onset 10–30 minutes)
    • Lispro (Humalog): peak 30−90 min30-90\ \text{min}; duration 3−6 hr3-6\ \text{hr}
    • Aspart (NovoLog): peak 1−3 hr1-3\ \text{hr}; duration 3−5 hr3-5\ \text{hr}
    • Short-acting insulin
    • Regular insulin (Humulin R, Novolin R)
    • Subcutaneous onset: 30−60 min30-60\ \text{min}; peak 2−4 hr2-4\ \text{hr}; duration 6−10 hr6-10\ \text{hr}
    • Intravenous (IV) onset: 10−30 min10-30\ \text{min}
    • Regular insulin is the only insulin suitable for IV use
    • Intermediate-acting insulin
    • NPH (Novolin N): onset 1−2 hr1-2\ \text{hr}; peak 6−14 hr6-14\ \text{hr}; duration 16 hrs16\ \text{hrs}
    • Hypoglycemia most likely at the peak
    • Typically given once daily for basal coverage
    • Long-acting insulin
    • Glargine (Lantus): onset 3−4 hr3-4\ \text{hr}; no peak; duration 24 hrs24\ \text{hrs}
    • Cannot be mixed with other insulins
    • Insulin Detemir: onset 3−4 hr3-4\ \text{hr}; peak 6−8 hr6-8\ \text{hr}; duration 18−24 hr18-24\ \text{hr}
    • Cannot be mixed with other insulins
  • Key cautions and considerations
    • Given at bedtime (HS) for long-acting basal coverage; steady overnight coverage
    • Do not mix glargine or detemir with other insulins in the same syringe
  • Adverse effects
    • Hypoglycemia
    • Local injection-site reactions
    • Lipodystrophy at injection sites
  • Special nursing considerations (section highlights)
    • Breastfeeding is possible, but the amount/quality of breast milk may be affected; assess infant nutrient intake
  • Contraindications
    • Hypoglycemia (acute contraindication)
  • Drug–drug interactions (insulin-influencing glucose balance)
    • Agents/conditions that increase glucose requirements (need more insulin):
    • Thiazide diuretics
    • Corticosteroids
    • Stress (illness, surgery)
    • Agents that decrease glucose levels (must monitor for hypoglycemia):
    • Salicylates
    • Other oral antidiabetic meds
    • Beta-blockers (may mask signs of hypoglycemia and blunt typical symptoms)
  • Nursing considerations for insulin (assessment)
    • Collect data on: Injection site integrity, vital signs, and glucose levels before/after dosing (timing depends on insulin onset)
    • Monitor activity level, nutritional intake, and glycosuria (urine glucose)
    • Monitor signs/symptoms of hypoglycemia (most often at peak)
  • Nursing considerations for insulin (administration and teaching)
    • Rotate injection sites to prevent lipodystrophy
    • If mixing NPH and Regular insulin, administer within 15 minutes15\ \text{minutes} of mixing
    • Patient education topics:
    • Rotate sites; monitor for N/V or fever and report to provider (increased insulin needs when ill)
    • Recognize signs of hyperglycemia and hypoglycemia
    • If hypoglycemic: consume fast-acting carbohydrate (e.g., candy, orange juice, honey, sugar)
    • Consider exercise/activity levels when planning eating and insulin doses
    • Avoid alcohol
    • Do not take OTC meds or herbs without provider consultation
    • Consider wearing a medic alert bracelet

Sulfonylureas

  • Common agents (2nd generation) and brand names
    • Glimepiride (Amaryl)
    • Glipizide (Glucotrol)
    • Glyburide (DiaBeta)
  • Indications and uses
    • Adjunct to diet control for Type II diabetes
    • Increase insulin secretion
    • Increase sensitivity to insulin
  • Adverse effects
    • Hypoglycemia
    • GI upset
    • Anorexia
    • Allergic skin reactions
    • Potentially increased cardiovascular mortality risk
  • Contraindications
    • Type I diabetes
    • Pregnancy and lactation
    • Pediatric patients
  • Drug–drug interactions
    • Beta-blockers
    • Alcohol
    • Herbal therapies (various herb-drug interactions)
    • Note: Care with other agents that affect glucose balance

Biguanides (Metformin) – Often listed under baglinides in some materials

  • Metformin (Glucophage) – PO
  • Therapeutic indications
    • Type II diabetes
    • Adjunct to diet and exercise
    • Only oral medication approved for children 10 years of age and older
  • Max dose (pediatric): 2000 mg/day2000\ \text{mg/day}
  • Mechanism of action
    • Decrease hepatic glucose production
    • Decrease intestinal glucose absorption
  • Side effects
    • Lactic acidosis risk (serious)
    • GI distress
    • Decreased appetite
    • Hypoglycemia (less common when used alone)
  • Interactions and safeguards
    • Alcohol can induce lactic acidosis risk
    • IV contrast (hold the day of and for 48 hours after procedures to reduce lactic acidosis risk)
    • Hold 1–2 days before procedures; hold 48 hours after
    • Surgical considerations may require holding 48 hours before and after
  • Nursing considerations
    • Take with breakfast (with food)
    • Monitor glucose levels
    • Patient teaching: how to monitor glucose; avoid alcohol; inform provider before tests or surgeries if taking metformin; report infection, dehydration, or diarrhea (risk for lactic acidosis)

Oral antidiabetics – Nursing considerations

  • Take with breakfast (with food)
  • Monitor glucose levels regularly
  • Patient teaching topics
    • How to monitor glucose
    • Avoid alcohol
    • Notify provider before scheduled tests or surgeries if taking metformin
    • Report infection, dehydration, or diarrhea to provider due to lactic acidosis risk

Glucose Elevating Agent – Glucagon

  • Glucagon (GlucaGen)
  • Doses
    • Adult: 0.5−1 mg0.5-1\ \text{mg} subcutaneous (subQ), intramuscular (IM), or intravenous (IV)
    • Pediatric: 0.5 mg0.5\ \text{mg} subQ, IM, or IV
  • Indication
    • Severe hypoglycemia
    • Unconscious patient with no IV access
  • Mechanism of action
    • Decrease insulin release
    • Accelerate breakdown of glycogen in the liver (glycogenolysis)
  • Cautions
    • Pregnancy and lactation considerations
    • Cardiovascular disease considerations
  • Adverse effects
    • GI upset/N/V
    • Hyperglycemia (as a rebound effect after administration)
  • Drug–drug interactions
    • Increased effect with anticoagulants

Nursing Considerations for Glucagon

  • Assess/Monitor
    • Vitals
    • Glucose levels
    • Nutritional status
    • Orientation
  • Practical notes
    • Air-brief: ensure availability of emergency supplies and access to glucose monitoring
    • After administration, monitor patient response and recheck glucose until stable
    • Ready-to-use administration in acute settings; ensure patient/family education for home use when prescribed

Connections to foundational principles and real-world relevance:

  • The insulin framework demonstrates the pharmacokinetic profiles crucial for timing administration with meals (rapid-acting vs. long-acting) and the importance of bedtime dosing for basal coverage.
  • Understanding drug interactions helps anticipate hypo- or hyperglycemic episodes, particularly in patients on polypharmacy (e.g., beta-blockers masking hypoglycemia signs).
  • The insistence on orange-capped syringes and IV-only use of regular insulin highlights patient safety and hospital protocol importance.
  • Metformin’s emphasis on holding around IV contrast and surgery reflects the risk of lactic acidosis, a key safety principle in pharmacology.
  • Glucagon serves as a critical rescue therapy for severe hypoglycemia, illustrating the real-world need for rapid-acting interventions when IV access is unavailable.

Ethical and practical implications:

  • Ensuring informed consent and patient education about hypoglycemia recognition and treatment options.
  • Balancing insulin therapy in pregnancy (gestational diabetes) and breastfeeding considerations to optimize both maternal and infant health.
  • Managing therapy with pediatric patients requires careful dosing considerations and family education due to growth and development factors.

Formulas and key values (for quick reference):

  • Insulin vial concentration: 100 units/mL100\ \text{units/mL}
  • Reg insulin IV onset: 10−30 min10-30\ \text{min}
  • Regular insulin duration (subQ): 6−10 hr6-10\ \text{hr}
  • Regular insulin duration (IV): notapplicable;IVonsetnot applicable; IV onset10-30\ \text{min}
  • NPH duration: 16\ \text{hrs}
  • Glargine: 24\ \text{hrs}
  • Detemir: 18-24\ \text{hrs}
  • Metformin max pediatric dose: 2000\ \text{mg/day}
  • Glucagon adult dose: 0.5-1\ \text{mg}
  • Glucagon pediatric dose: 0.5\ \text{mg}$$
  • Hold metformin around IV contrast: hold 48 hours before and after procedure