What antihypertensive medications should be prescribed to patients not eligible for thrombolysis?

Antihypertensive Medications for Patients Not Eligible for Thrombolysis

For patients with acute ischemic stroke who are not eligible for thrombolysis, blood pressure should generally not be treated unless systolic BP exceeds 220 mmHg or diastolic BP exceeds 120 mmHg, with labetalol and nicardipine being the first-line agents when treatment is required. 1, 2

Blood Pressure Management Algorithm

When NOT to Treat Blood Pressure

• For systolic BP <220 mmHg or diastolic BP <120 mmHg:
  • Observe without antihypertensive treatment
  • Focus on treating other symptoms of stroke (headache, pain, agitation, nausea, vomiting)
  • Address other acute complications (hypoxia, increased intracranial pressure, seizures, hypoglycemia) 1

When to Treat Blood Pressure

1. Systolic BP >220 mmHg or diastolic BP 121-140 mmHg:

   • First-line options:
     • Labetalol: 10-20 mg IV over 1-2 minutes; may repeat or double every 10 minutes (maximum dose 300 mg) 1, 2, 3
     • OR
     • Nicardipine: 5 mg/h IV infusion as initial dose; titrate by increasing 2.5 mg/h every 5 minutes to maximum of 15 mg/h 1, 2, 4
   • Target: Aim for a 10-15% reduction in blood pressure (not more than 25%) 1, 2

2. Diastolic BP >140 mmHg:

   • First-line option:
     • Sodium nitroprusside: 0.5 μg/kg/min IV infusion as initial dose with continuous blood pressure monitoring 1
   • Target: Aim for a 10-15% reduction in blood pressure 1

Medication Considerations

Labetalol

• Combined alpha-1 and non-selective beta-adrenergic blocker 3
• Advantages:
  • Leaves cerebral blood flow relatively intact 1
  • Does not increase intracranial pressure 1
  • Rapid onset of action (5-10 minutes) 5
• Caution in patients with:
  • Bradycardia
  • Heart block
  • Bronchospastic disease
  • Decompensated heart failure 3

Nicardipine

• Dihydropyridine calcium channel blocker 4
• Advantages:
  • Easily titratable 4
  • Effective at reducing blood pressure 5
• Caution in patients with:
  • Advanced aortic stenosis
  • Heart failure 4

Sodium Nitroprusside

• Should be used with caution due to:
  • Potential increases in intracranial pressure
  • Adverse effects on cerebral autoregulation
  • Risk of cyanide toxicity with prolonged use 2, 6
• Reserved for cases of severe hypertension not responsive to other agents 6

Important Clinical Considerations

1. Permissive Hypertension: The rationale for allowing relatively high blood pressure (up to 220/120 mmHg) in acute ischemic stroke is to maintain cerebral perfusion pressure in the setting of impaired autoregulation 2

2. Avoid Excessive BP Reduction: Rapid and excessive lowering of blood pressure can worsen cerebral ischemia by reducing perfusion to the ischemic penumbra 1, 2

3. Monitoring: When treating hypertension in acute stroke patients, close monitoring is essential:

   • Check blood pressure every 15 minutes during active treatment
   • Continue monitoring frequently after achieving target BP 2

4. Special Circumstances: Lower BP targets may be appropriate for patients with comorbid conditions like:

   • Acute myocardial infarction
   • Heart failure
   • Aortic dissection
   • Hypertensive encephalopathy 1, 2

5. Transition to Oral Therapy: Once the acute phase has passed (after several days), initiate or restart oral antihypertensive medications for long-term management 1, 2

By following this evidence-based approach to blood pressure management in patients with acute ischemic stroke who are not eligible for thrombolysis, you can help minimize the risk of complications while optimizing patient outcomes.