Which blood pressure medication should be adjusted in a patient with hypotension?

Managing Hypotension in a Patient on Multiple Antihypertensive Medications

The hydralazine 25 mg oral tablet should be discontinued first due to its direct vasodilatory effect and the patient's current hypotensive state (89/68 mmHg, rechecked at 102/70 mmHg). 1

Assessment of Current Blood Pressure Status

The patient is experiencing hypotension with initial readings of 89/68 mmHg followed by 102/70 mmHg after 30 minutes. This represents a significant concern as:

• Blood pressure below 90/60 mmHg is considered hypotensive
• The patient is on multiple antihypertensive medications:
  • Amlodipine 5 mg twice daily (calcium channel blocker)
  • Hydralazine 25 mg twice daily (direct vasodilator)
  • Losartan 50 mg twice daily (angiotensin receptor blocker)
  • Metoprolol 25 mg twice daily (beta-blocker)

Prioritizing Medication Adjustments

When managing hypotension in patients on multiple antihypertensive medications, a systematic approach is needed:

1. First-line adjustment: Discontinue hydralazine

   • Hydralazine is a direct vasodilator that can cause significant hypotension
   • Research shows hydralazine causes a mean BP reduction of 24/9 mmHg when given intravenously 2
   • Even oral hydralazine results in significant BP lowering effects 3
   • Hydralazine has been associated with hypotension as its most common adverse effect 2

2. Second-line adjustment (if needed):

   • Consider reducing amlodipine from twice daily to once daily
   • Calcium channel blockers can cause peripheral vasodilation and contribute to hypotension

3. Third-line adjustment (if needed):

   • Reduce losartan dose or frequency
   • According to FDA labeling, losartan starting dose should be 25 mg in patients with possible intravascular depletion 4

Rationale for Hydralazine Discontinuation

Hydralazine is particularly problematic in this hypotensive patient for several reasons:

• It acts as a direct arterial vasodilator with minimal effect on venous capacitance vessels
• It can cause reflex tachycardia and fluid retention
• It has been associated with higher rates of hypotension compared to other antihypertensives 2
• The European Society of Cardiology guidelines note that hydralazine should be used with caution in patients with symptomatic orthostatic hypotension 5

Monitoring After Medication Adjustment

After discontinuing hydralazine:

• Monitor blood pressure every 4-6 hours for the first 24 hours
• If blood pressure remains low (<100/70 mmHg), consider further medication adjustments
• If blood pressure normalizes (>120/70 mmHg), maintain current regimen without hydralazine
• Check electrolytes, particularly potassium, as the patient is on multiple agents affecting the renin-angiotensin-aldosterone system

Important Considerations

• Avoid abrupt discontinuation of beta-blockers (metoprolol): This can lead to rebound hypertension and tachycardia
• Monitor for orthostatic changes: Have the patient change positions slowly and monitor for dizziness
• Consider underlying causes: Evaluate for other causes of hypotension such as dehydration, infection, or cardiac issues
• Medication timing: If hypotension is more pronounced at certain times of day, consider adjusting the timing of remaining antihypertensive medications

Pitfalls to Avoid

• Do not discontinue multiple antihypertensive medications simultaneously: This can lead to rebound hypertension
• Do not ignore recurrent hypotension: If hypotension persists after hydralazine discontinuation, further medication adjustments will be necessary
• Avoid combining RAS blockers: The patient is already on losartan; adding an ACE inhibitor would increase hypotension risk 5
• Do not maintain the same regimen: Continuing all current medications despite documented hypotension could lead to falls, syncope, or end-organ damage

By discontinuing hydralazine first, you address the most likely contributor to hypotension while maintaining the core antihypertensive regimen that may be necessary for the patient's underlying conditions.