Anti-Dysrhythmic Medications Lecture Notes

Overview

• Topics Covered: Cardiac glycosides, Class 1 and 2 anti-dysrhythmic medications.
• Focus Medication: Digoxin (cardiac glycoside).

Cardiac Glycosides

Digoxin

• Uses: Heart failure, atrial fibrillation, and atrial flutter.
• Mode of Action:
  • Positive inotropic effect (increases contraction force and efficiency).
  • Negative chronotropic effect (decreases heart rate).
• Side Effects:
  • Dysrhythmias (e.g., bradycardia).
  • Digoxin toxicity (monitor for GI upset, fatigue, weakness, vision issues).
• Administration Notes:
  • Check pulse before administration; hold if <60 bpm.
  • Monitor digoxin levels (therapeutic range: 0.5-2 ng/mL).
  • Hypokalemia increases toxicity risk.
  • Treat bradycardia with atropine; treat toxicity with digoxin immune fab (DigiBind).
• Mnemonic Tip: "Dig slow and deep"—digoxin slows and strengthens heart contractions.

Class 1 Anti-Dysrhythmics

Sodium Channel Blockers

• Examples: Procainamide, Lidocaine (both contain "cane").
• Uses: Ventricular dysrhythmias, supraventricular tachycardia.
• Side Effects:
  • Hypotension, dysrhythmias, lupus, leukopenia, thrombocytopenia.
  • Black box warning: prolonged use of procainamide may cause ANA positive autoimmune response.
• Monitoring: EKG, vital signs, CBC, blood levels (therapeutic: 4-8 mcg/mL).

Class 2 Anti-Dysrhythmics

Beta Blockers

• Examples: Propranolol, Metoprolol, Atenolol.
• Uses: Dysrhythmias (atrial fibrillation, atrial flutter, ventricular dysrhythmias).
• Side Effects:
  • Hypotension, bradycardia, fatigue, weakness, erectile dysfunction.
  • Non-selective beta blockers (e.g., propranolol) can cause bronchospasm (avoid in asthma patients).
• Beta Blocker Types:
  • Beta 1 Blockers (Metoprolol, Atenolol): safer for asthma patients.
  • Non-selective Beta Blockers (Propranolol, Libidolol, Carvedilol): affect beta-1 and beta-2 receptors, causing bronchoconstriction.
• Mnemonic:
  • "One ma" for beta 1 blockers (Metoprolol, Atenolol).
  • "Please listen carefully" for non-selective (Propranolol, Libidolol, Carvedilol).

Conclusion

• Next session will cover classes 3, 4, and 5 anti-dysrhythmic medications.
• Encouragement to engage with video content and share for educational support.