What to do if propranolol (beta blocker) 10mg is causing bradycardia?

Management of Propranolol-Induced Bradycardia

Discontinue propranolol immediately and consider atropine administration if the bradycardia is symptomatic or severe. 1

Assessment of Bradycardia Severity

When propranolol causes bradycardia, the first step is to determine the severity:

1. Asymptomatic bradycardia:

   • Heart rate <60 bpm but patient has no symptoms
   • Monitor closely but may not require immediate intervention

2. Symptomatic bradycardia:

   • Heart rate typically <50 bpm with symptoms 2
   • Symptoms may include: dizziness, lightheadedness, syncope, altered mental status, hypotension, chest discomfort, or signs of shock
   • Requires prompt intervention

Immediate Management Algorithm

Step 1: Discontinue Propranolol

• Stop the medication immediately
• Even at low doses like 10mg, propranolol can cause significant bradycardia in sensitive individuals

Step 2: For Symptomatic Bradycardia

• Administer atropine:
  • Initial dose: 0.5-1.0 mg IV 2
  • May repeat up to a total of 1.5-2.0 mg 2
  • Monitor response

Step 3: If Bradycardia Persists or Is Severe

• Consider glucagon:

  • 50-150 mcg/kg IV bolus followed by continuous infusion of 1-5 mg/hour 1
  • Glucagon works by bypassing beta-receptors and can reverse propranolol-induced bradycardia

• Consider isoproterenol:

  • May be used for persistent bradycardia unresponsive to atropine 1
  • Caution: may cause uncontrolled hypertension if used with epinephrine

• Temporary cardiac pacing:

  • For serious bradycardia unresponsive to pharmacological interventions 1

Monitoring and Supportive Care

• Continuous cardiac monitoring
• Regular vital sign checks
• Monitor for hypotension (another common side effect of propranolol)
• IV access should be maintained
• Consider 12-lead ECG to rule out heart block or other conduction abnormalities

Special Considerations

• Underlying cardiac conditions: Patients with pre-existing cardiac disease may be more susceptible to propranolol-induced bradycardia 2

• Concomitant medications: Check for other medications that may potentiate bradycardia (calcium channel blockers, digoxin) 2

• Dose adjustment: If propranolol is absolutely necessary for the patient's condition, consider:

  1. Lower dose when restarting
  2. More frequent monitoring
  3. Alternative beta-blockers with less effect on heart rate

Prevention of Recurrence

• Consider alternative medications if appropriate
• If propranolol must be continued (e.g., for infantile hemangioma), consider:
  • Dose reduction 2
  • Cardiac monitoring during therapy initiation
  • Patient/caregiver education about symptoms of bradycardia 2

When to Seek Specialist Consultation

• Persistent symptomatic bradycardia despite interventions
• Patients with complex cardiac history
• Need for temporary pacing
• Recurrent episodes of bradycardia with propranolol despite dose adjustments

Remember that propranolol-induced bradycardia is a direct pharmacological effect of beta-blockade and usually resolves after discontinuation of the medication, though the half-life of propranolol means this may take several hours.