What is the best treatment for a 79-year-old male with dizziness, bradycardia, and orthostatic hypotension taking metoprolol succinate, hydrochlorothiazide, and losartan?

Management of Dizziness in a 79-Year-Old Male with Bradycardia and Orthostatic Hypotension

The most appropriate treatment is to discontinue metoprolol succinate, which is likely causing symptomatic bradycardia and contributing to orthostatic hypotension in this elderly patient.

Assessment of Current Medication-Related Issues

Bradycardia and Metoprolol

• The patient's Holter monitor shows sinus bradycardia with an average heart rate of 59 and a low of 44 bpm
• Metoprolol succinate is a beta-blocker that can cause:
  • Bradycardia (heart rate <60 bpm)
  • Exacerbation of orthostatic hypotension
  • Fatigue and dizziness 1
• FDA labeling warns that bradycardia, including sinus pause, heart block, and cardiac arrest can occur with metoprolol use 2

Orthostatic Hypotension Contributing Factors

• The patient has positive orthostatic blood pressure changes
• Multiple medications are contributing to orthostatic hypotension:
  • Metoprolol (beta-blocker)
  • Hydrochlorothiazide (thiazide diuretic)
  • Losartan (angiotensin receptor blocker) 3
• Elderly patients (≥75 years) are at higher risk of orthostatic hypotension with these medications 3, 4
• Drug-induced orthostatic hypotension can lead to falls, syncope, and injury 4

Treatment Algorithm

Step 1: Discontinue Metoprolol

• Metoprolol should be discontinued as it is the most likely cause of symptomatic bradycardia 2
• Important: Taper gradually over 1-2 weeks rather than abruptly stopping to avoid rebound effects 2

Step 2: Adjust Remaining Antihypertensive Medications

• Consider reducing the dose of hydrochlorothiazide

  • Thiazide diuretics can cause hypovolemia and worsen orthostatic hypotension 3, 5
  • Lower starting doses (12.5 mg) are recommended in elderly patients 5

• Maintain losartan as the primary antihypertensive

  • Angiotensin receptor blockers generally have fewer orthostatic effects than beta-blockers 6
  • Losartan may be better tolerated in elderly patients with orthostatic hypotension 7, 6

Step 3: Monitor Response

• Check orthostatic vital signs after medication changes
• Reassess symptoms of dizziness
• Monitor heart rate to ensure it returns to appropriate range
• If bradycardia persists despite metoprolol discontinuation, further cardiac evaluation may be needed

Important Considerations and Precautions

Medication Interactions

• The combination of beta-blockers, diuretics, and ARBs increases the risk of orthostatic hypotension, especially in elderly patients 3
• Elderly patients (>75 years) are particularly susceptible to drug-induced orthostatic hypotension due to:
  • Decreased baroreceptor sensitivity
  • Altered pharmacokinetics
  • Reduced physiologic reserve 8

Monitoring Parameters

• Heart rate and rhythm
• Blood pressure (both supine and standing)
• Symptoms of dizziness, fatigue, or syncope
• Electrolytes, especially if continuing hydrochlorothiazide 3, 5

Common Pitfalls to Avoid

1. Abrupt discontinuation of beta-blockers - can cause rebound hypertension or exacerbation of underlying cardiovascular conditions 2
2. Failure to recognize medication-induced bradycardia - beta-blockers are a common cause of symptomatic bradycardia in elderly patients 1, 2
3. Excessive antihypertensive therapy - can lead to orthostatic hypotension and falls in elderly patients 8
4. Ignoring orthostatic hypotension - which increases risk of falls and injury 4

By discontinuing metoprolol and optimizing the remaining antihypertensive regimen, the patient's symptoms of dizziness should improve while maintaining adequate blood pressure control.