What oral medications are used to treat symptomatic bradycardia?

Oral Medications for Symptomatic Bradycardia

Theophylline is the primary oral medication recommended for treating symptomatic bradycardia, particularly in patients with sinus node dysfunction where a trial of oral theophylline may be considered to increase heart rate and improve symptoms before proceeding to permanent pacing. 1

First-Line Oral Therapy

• Theophylline (oral) may be considered in patients with symptoms likely attributable to sinus node dysfunction (SND) to increase heart rate, improve symptoms, and help determine potential effects of permanent pacing 1
• Oral theophylline is particularly useful in specific clinical scenarios:
  • After inferior myocardial infarction 1
  • In cardiac transplant patients 1
  • In patients with spinal cord injury 1, 2

Mechanism and Dosing

• Theophylline works by inhibiting phosphodiesterase, increasing cyclic adenosine monophosphate (cAMP) levels, and activating the sympathoadrenal system 2
• While IV dosing is typically 100-200 mg slow injection (maximum 250 mg), oral dosing must be individualized based on patient factors and response 1

Clinical Considerations and Limitations

• Oral medications have limited utility in acute, hemodynamically unstable bradycardia, which requires IV medications or temporary pacing 3
• Theophylline may have side effects including nausea, headache, insomnia, and at higher levels, seizures
• Regular monitoring of theophylline levels is recommended to maintain therapeutic effect while avoiding toxicity

Alternative Management Approaches

• For most symptomatic bradycardia cases, permanent pacing remains the definitive treatment when bradycardia is persistent and symptomatic 1, 4
• In patients with tachy-brady syndrome and symptoms attributable to bradycardia, permanent pacing is reasonable to increase heart rate and reduce symptoms 1, 3
• For acute symptomatic bradycardia, IV medications remain first-line:
  • Atropine (0.5-1 mg IV every 3-5 minutes, maximum 3 mg) 1, 3
  • If atropine fails, second-line options include:
    • Epinephrine (2-10 μg/min) 1, 3
    • Dopamine (2-10 μg/kg/min) 1, 3
    • Isoproterenol (for AV block with low likelihood of coronary ischemia) 1, 3

Special Populations and Precautions

• In heart transplant patients, atropine should be used with caution as it may paradoxically cause high-degree AV block due to denervation 1, 3
• Small doses of atropine (<0.5 mg) may paradoxically worsen bradycardia due to central vagal stimulation 3, 5
• Patients with infranodal heart blocks (at His-Purkinje level) may have adverse responses to atropine 5

Emerging Options

• Glucagon may have a role in treating drug-induced symptomatic bradycardia, particularly in the presence of beta-adrenergic blockade or calcium channel blockade, though this is not yet in mainstream guidelines 6