When should blood pressure medication be started in a patient who has experienced a stroke?

When to Start Blood Pressure Medication After a Stroke

For patients with acute ischemic stroke who are neurologically stable and have pre-existing hypertension, restart antihypertensive medications after the first 24 hours, while those not previously treated should wait until after 48-72 hours (or 3 days) before initiating blood pressure medications unless BP exceeds 220/120 mmHg. 1

Timing Based on Thrombolysis Status

Patients Receiving Thrombolysis or Thrombectomy

• Blood pressure must be lowered to <185/110 mmHg before administering IV thrombolysis and maintained <180/105 mmHg for at least 24 hours after treatment to minimize the risk of symptomatic intracranial hemorrhage. 1
• This aggressive BP management is necessary because reperfusion therapy increases the risk of hemorrhagic transformation. 1

Patients NOT Receiving Reperfusion Therapy

First 48-72 Hours (Permissive Hypertension Phase):

• Do not initiate or restart antihypertensive medications if BP is <220/120 mmHg during the first 48-72 hours, as lowering BP in this range has not been shown to prevent death or dependency and may worsen outcomes. 1, 2
• The rationale is that cerebral autoregulation is impaired during acute stroke, and the ischemic penumbra depends on systemic blood pressure to maintain perfusion. 1, 2
• Studies demonstrate a U-shaped relationship between BP and outcomes, with optimal systolic BP ranging from 121-200 mmHg. 1

Exception for Extremely High BP:

• If BP reaches ≥220/120 mmHg, consider carefully lowering BP by approximately 15% over the first 24 hours. 1
• Use IV labetalol or nicardipine with gradual titration to avoid precipitous drops. 1

When to Restart or Initiate Antihypertensive Therapy

For Previously Treated Hypertensive Patients

• Restart antihypertensive medications after 24 hours if the patient is neurologically stable and has no contraindications. 1
• This recommendation is based on the need to improve long-term BP control for secondary stroke prevention. 1
• The COSSACS trial showed that continuing antihypertensives after acute stroke was safe, with no increase in adverse events despite lower BP levels. 3

For Previously Untreated Patients

• Wait until after 3 days (72 hours) post-stroke to initiate antihypertensive therapy if BP remains ≥140/90 mmHg and the patient is neurologically stable. 1, 2
• Starting treatment earlier in patients without pre-existing hypertension and BP <220/120 mmHg is not effective and may be harmful. 1

Secondary Prevention Considerations

After the Acute Phase:

• All patients with stroke or TIA and established BP ≥140/90 mmHg should receive antihypertensive treatment for secondary prevention. 1
• Preferred agents include thiazide diuretics, ACE inhibitors, ARBs, or combination therapy (thiazide plus ACE inhibitor). 1
• A BP goal of <130/80 mmHg may be reasonable for long-term secondary prevention, though this is based on moderate evidence. 1, 2
• Antihypertensive therapy reduces recurrent stroke risk by approximately 30% in meta-analyses. 1, 4

Critical Pitfalls to Avoid

• Never aggressively lower BP in the first 48-72 hours unless BP is ≥220/120 mmHg or the patient is receiving thrombolysis, as this can compromise cerebral perfusion and worsen outcomes. 1, 2
• Avoid rapid BP reduction (>15% in 24 hours or >70 mmHg drop), which can cause acute renal injury and early neurological deterioration. 1, 2
• Do not automatically restart home antihypertensive medications in the first 24-48 hours without considering the patient's neurological stability and current BP. 2
• Avoid calcium channel blockers like nicardipine in the acute phase unless specifically indicated, as they may cause excessive BP drops and impair cerebral blood flow. 5

Monitoring Requirements

• Check BP frequently (every 15 minutes initially, then hourly) during the acute phase, especially in patients receiving thrombolysis. 1
• Assess neurological status with each BP measurement to detect early deterioration. 1
• Monitor for hypotension, which is potentially more harmful than hypertension in acute stroke. 1