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Alpha-2 adrenergic agonists: Nursing Pharmacology

Notes

Notes

ALPHA-2 ADRENERGIC AGONISTS
DRUG NAME
clonidine (Catapres-TTS, Duraclon, Kapvay), guanfacine (Intuniv), methyldopa 
CLASS
α2 selective adrenergic agonists
MECHANISM of ACTION
Stimulate presynaptic α2-adrenergic receptors in the CNS → dilates peripheral blood vessels → lowers peripheral resistance → reduces blood pressure
INDICATIONS
  • Hypertension

Clonidine:
  • Pain management (epidural)
  • Attention-deficit / hyperactivity disorder (ADHD)

Methyldopa:
  • Hypertensive crisis
ROUTE(S) of ADMIN
  • Clonidine: PO, TD, Epidural
  • Guanfacine: PO
  • Methyldopa: PO, IV
SIDE EFFECTS
  • Nausea, vomiting, constipation, dry mouth
  • Bradycardia
  • Clonidine: rebound hypertension when stopped abruptly, CNS depression
  • Guanfacine, methyldopa: orthostatic hypotension, sedation
  • Methyldopa: granulocytopenia, thrombocytopenia, hemolytic anemia, hepatotoxicity, hepatic necrosis
CONTRAINDICATIONS & CAUTIONS
  • Pregnancy and breastfeeding
  • Children and elderly clients
  • Cardiovascular, cerebrovascular, or renal disease
  • Clonidine: epidural use for obstetrical, postpartum, or perioperative pain management not recommended (boxed warning)
  • Methyldopa: active hepatic disease, MAO inhibitors

Drug interactions:
  • Clonidine: verapamil, diltiazem, beta-blockers
  • Methyldopa: lithium, MAO inhibitors, levodopa
NURSING CONSIDERATIONS for
ALPHA-2 ADRENERGIC AGONISTS
ASSESSMENT & MONITORING
Assess
  • Vital signs, especially blood pressure and heart rate
  • Laboratory test results; renal function 

Monitor
  • Side effects
  • Evaluate therapeutic response: blood pressure within a normal range 
CLIENT EDUCATION
  • Purpose of medication: blood pressure control
  • Transdermal patch
    • Apply every seven days at a consistent time each week
    • Apply to a clean, dry, intact and hairless skin
      • Chest or upper arm preferred
      • Rotate the application site 
      • Proper disposal of a used patch
  • Do not discontinue abruptly
    • Notify healthcare provider for symptoms of hypertension: sweating, flushing, nervousness, severe headache, blurred vision
  • Side effects
    • Nausea, vomiting, constipation
      • Management: consuming smaller, more frequent meals; increasing fluids, fiber-rich foods 
    • Dry mouth, suggest
      • Use sugar-free hard candy or gum; frequent sips of water
    • Drowsiness
      • Avoid alcohol or other CNS depressants
      • Avoid activities that require alertness
    • Dizziness, bradycardia and hypotension
      • Make position changes slowly; use caution when going up and down stairs
  • Lifestyle modifications for blood pressure management
    • Weight loss, smoking cessation, increased physical activity as tolerated, low sodium diet
    • Blood pressure self-monitoring
      • Abnormal readings that warrant medical attention
Sources
  1. "Focus on Nursing Pharmacology" LWW (2019)
  2. "Pharmacology - A Patient-Centered Nursing Process Approach (8e)" Elsevier Health Sciences (2014)
  3. "Mosby's 2021 Nursing Drug Reference" Mosby (2020)
  4. "Saunders Comprehensive Review for the NCLEX-RN® Examination (7e)" Saunders (2017)