What medications can be used to increase heart rate (HR) and blood pressure (BP) in outpatients with bradycardia and hypotension?

Medications for Increasing Heart Rate and Blood Pressure in Outpatients

For outpatients with bradycardia and hypotension, midodrine is the most effective oral medication to increase both heart rate and blood pressure, with a starting dose of 2.5-5 mg three times daily (maximum 10 mg per dose). 1

First-Line Medications

Midodrine

• FDA-approved alpha-1 adrenergic agonist specifically for orthostatic hypotension 1
• Dosing: Start with 2.5-5 mg three times daily, with last dose at least 3-4 hours before bedtime 1
• Increases standing systolic blood pressure by approximately 15-30 mmHg within 1 hour of administration 1
• Duration of action: 2-4 hours, with peak effect at 1-2 hours 1
• Particularly effective for patients with neurogenic orthostatic hypotension 2

Atropine

• Recommended for symptomatic bradycardia with associated hemodynamic compromise 3
• Dosage: 0.5-1 mg IV (may be repeated every 3-5 minutes to maximum 3 mg) 3
• Blocks muscarinic acetylcholine receptors, facilitating sinoatrial conduction and increasing sinus node automaticity 3
• Half-life of approximately 2 hours 3
• Not effective in heart transplant patients without autonomic reinnervation 3

Beta Agonists

• May be considered for symptomatic bradycardia with hemodynamic compromise in patients at low risk for coronary ischemia 3
• Options include:
  • Isoproterenol: 20-60 mcg IV bolus followed by 1-20 mcg/min infusion 3
  • Dopamine: 5-20 mcg/kg/min IV infusion 3
  • Epinephrine: 2-10 mcg/min IV or 0.1-0.5 mcg/kg/min IV 3
• These agents have both chronotropic and inotropic effects 3

Second-Line Options

Pseudoephedrine

• Over-the-counter sympathomimetic that can increase both heart rate and blood pressure 2
• Has been used successfully to facilitate weaning from IV vasopressors in patients with refractory bradycardia and hypotension 2
• Caution: May enhance pressor effects when used with midodrine 1

Aminophylline/Theophylline

• Reasonable option for specific situations:
  • Post-heart transplant patients 3
  • Spinal cord injury with symptomatic bradycardia 3
• Aminophylline dosing: 250 mg IV bolus or 6 mg/kg in 100-200 mL IV fluid over 20-30 minutes 3
• Theophylline dosing: Oral dose of 5-10 mg/kg/day titrated to effect 3

Treatment Algorithm

1. Assess severity and etiology:

   • Determine if bradycardia and hypotension are symptomatic (dizziness, syncope, fatigue) 3
   • Rule out reversible causes (medications, electrolyte abnormalities, hypothyroidism) 3

2. For mild to moderate symptoms in outpatients:

   • Start midodrine 2.5-5 mg three times daily (last dose 3-4 hours before bedtime) 1
   • Titrate up to 10 mg three times daily as needed and tolerated 1
   • Monitor for supine hypertension, which is the most common adverse effect 1

3. For patients with inadequate response to midodrine:

   • Consider adding pseudoephedrine as adjunctive therapy 2
   • For specific populations (post-transplant, spinal cord injury), consider aminophylline/theophylline 3

4. For severe symptoms requiring immediate intervention:

   • Initiate temporary IV medications in hospital setting (atropine, dopamine, isoproterenol) 3
   • Transition to oral agents once stabilized 3

Special Considerations

Monitoring

• Regular blood pressure monitoring in both supine and standing positions 1
• Assess for signs of supine hypertension (headache, blurred vision, cardiac awareness) 1
• Monitor renal function, as desglymidodrine is eliminated via the kidneys 1

Common Pitfalls to Avoid

• Administering midodrine too close to bedtime, which increases risk of supine hypertension 1
• Using midodrine in patients with severe cardiac disease, as it may worsen existing conditions 1
• Failing to assess for drug interactions, particularly with other vasoconstrictors or cardiac medications 1
• Using atropine in heart transplant patients, where it is ineffective and potentially harmful 3

Drug Interactions

• Midodrine may interact with other vasoconstrictors, cardiac glycosides, beta-blockers, and MAO inhibitors 1
• Avoid concomitant use of midodrine with drugs that increase blood pressure (phenylephrine, ephedrine) 1
• Use caution when combining midodrine with fludrocortisone due to increased risk of supine hypertension 1

Contraindications

• Midodrine is contraindicated in patients with severe cardiac disease, acute renal failure, urinary retention, pheochromocytoma, or thyrotoxicosis 1
• Beta agonists should be avoided in patients with coronary artery disease or uncontrolled hypertension 3