Pharmacology of Adrenergic and Anticholinergic Drugs

Adrenergic Drugs

• Mimic the sympathetic nervous system (SNS)
• Epinephrine: Opens bronchi, increases blood pressure (anaphylaxis)
• Dopamine: Enhances cardiac output (shock management), improves heart rate and circulation
• Beta2-Adrenergic Receptors: Bronchodilation (asthma)
• Beta1-Adrenergic Receptors: Impact heart rate and contraction strength
• Patient Teaching: Do not abruptly stop beta-blockers (e.g., Atenolol) to avoid rebound hypertension, monitor pulse and blood pressure, be aware of hypoglycemia symptoms when using beta-blockers

Anticholinergic Drugs

• Block the parasympathetic nervous system (PNS) to reduce secretions and slow systems.
• Glycopyrrolate: Used pre-surgery to decrease oral and GI secretions
• Oxybutynin: Decreases urinary frequency, helps with bladder control
• Side Effects: Dry mouth, blurred vision, constipation
• Special notes for active seniors: Stay cool to prevent heat stroke; reduced sweating
• Precautions: Prevent dehydration with fiber-rich foods, plenty of water

Cholinergic Drugs

• Stimulate the PNS by increasing acetylcholine levels.
• Donepezil: Improves memory in Alzheimer's patients (not a cure)
• Bethanechol: Eases urinary retention after surgery
• Contraindications: Avoid in GI obstruction, bradycardia, or hypotension
• Patient teaching: Take bethanechol with meals to prevent nausea and vomiting

Disease-Specific Drug Applications

• Heart Conditions:
  • Carvedilol: Treats mild heart failure
  • Monitoring: Look for signs of worsening heart failure: weight gain, edema, shortness of breath
• Respiratory Management:
  • Albuterol: Helps during acute asthma attacks, may cause tachycardia
  • Salmeterol: Prevents, but does not treat, sudden asthma symptoms
• Neurological Focus:
  • Memantine: Used for Alzheimer's Disease to manage symptoms
  • Pyridostigmine: Improves swallowing in Myasthenia Gravis, take 30 minutes before meals

Clinical Scenarios

• Phentolamine: Prevents tissue damage from vasopressors like dobutamine.
• Physostigmine: Antidote for atropine overdose

Patient Education Essentials

• Safety Precautions:
  • Notify a doctor if pulse drops below 60 bpm while on beta-blockers
  • Avoid overheating when taking anticholinergics; stay hydrated
• Timing:
  • Apply Scopolamine patch 4–5 hours before travel for motion sickness
  • Schedule Cholinergic Drugs carefully with meals for best effect
• Herbal Awareness:
  • Ginkgo biloba increases bleeding risk when combined with aspirin