At what blood pressure should antihypertensives be held to prevent hypotension?

When to Hold Antihypertensive Medications

Antihypertensive medications should be held when systolic blood pressure is <90 mmHg or diastolic blood pressure is <60 mmHg to prevent hypotension and associated adverse outcomes.

Blood Pressure Thresholds for Holding Medications

The decision to hold antihypertensive medications should be based on specific blood pressure thresholds that indicate potential hypotension:

General Population

• Hold if:
  • Systolic BP <90 mmHg
  • Diastolic BP <60 mmHg

Special Populations

• Elderly or Frail Patients:

  • Consider holding at slightly higher thresholds (SBP <100 mmHg)
  • Individualize based on orthostatic symptoms

• Patients with Coronary Artery Disease:

  • Hold if SBP <100 mmHg to prevent coronary hypoperfusion

• Post-Myocardial Infarction:

  • As stated in the lisinopril drug label, "If hypotension occurs (systolic blood pressure ≤100 mmHg) a daily maintenance dose of 5 mg may be given with temporary reductions to 2.5 mg if needed. If prolonged hypotension occurs (systolic blood pressure <90 mmHg for more than 1 hour) lisinopril tablets should be withdrawn" 1

Clinical Context and Decision-Making Algorithm

1. Measure BP accurately:

   • Use validated device with appropriate cuff size
   • Take average of 2-3 readings
   • Consider home BP readings if available

2. Assess for symptoms of hypotension:

   • Dizziness, lightheadedness
   • Syncope or near-syncope
   • Fatigue or weakness
   • Mental status changes

3. Decision algorithm:

   • If SBP <90 mmHg or DBP <60 mmHg: Hold all antihypertensive medications
   • If SBP 90-100 mmHg: Consider holding medications in high-risk patients (elderly, CAD)
   • If patient has symptoms of hypotension regardless of BP reading: Hold medications and reassess

4. Medication-specific considerations:

   • Hold diuretics first (most likely to cause volume depletion)
   • Then vasodilators (ACE inhibitors, ARBs, calcium channel blockers)
   • Consider maintaining beta-blockers in patients with coronary disease unless severely hypotensive

Resuming Antihypertensive Therapy

When blood pressure returns to acceptable levels:

1. Restart at lower doses if BP rises above 110/70 mmHg
2. Reintroduce medications gradually, one at a time
3. Monitor BP closely after restarting therapy (within 1-2 days)
4. Consider permanent dose reduction if hypotension recurs

Common Pitfalls and Caveats

• Don't abruptly discontinue beta-blockers in patients with coronary artery disease (can precipitate angina or MI)
• Beware of rebound hypertension with sudden discontinuation of clonidine
• Consider medication timing - evening doses may cause more profound nocturnal hypotension
• Watch for orthostatic hypotension - measure BP both sitting and standing
• Evaluate for secondary causes of hypotension (dehydration, infection, adrenal insufficiency)
• Assess for drug interactions that may potentiate hypotensive effects

Target Blood Pressure Considerations

While the question addresses when to hold medications, it's worth noting the target BP ranges for context:

• General population: <140/90 mmHg 2
• Diabetes or chronic kidney disease: <130/80 mmHg 2
• Elderly patients: Consider higher targets based on frailty and comorbidities 2

Remember that these are target ranges for treatment, not thresholds for holding medications. The decision to hold medications is based on the risk of hypotension and its consequences, which generally occurs at much lower BP levels than treatment targets.