What is the recommended short‑term management for acute severe hypertension (hypertensive urgency or emergency), including drug choices, dosing, titration, and monitoring?

Short-Term Regulation of Blood Pressure in Hypertensive Crisis

Immediate Classification: Emergency vs. Urgency

The presence or absence of acute target-organ damage—not the absolute blood pressure number—determines whether you have a hypertensive emergency requiring immediate IV therapy in the ICU, or a hypertensive urgency manageable with oral agents as an outpatient. 1, 2

Hypertensive Emergency (BP ≥180/120 mmHg WITH acute organ damage)

• Neurologic damage: altered mental status, seizures, severe headache with vomiting, visual loss, focal deficits, hypertensive encephalopathy, stroke 1, 2
• Cardiac damage: acute MI, unstable angina, acute heart failure with pulmonary edema 1, 2
• Vascular damage: aortic dissection or aneurysm 1, 2
• Renal damage: acute kidney injury, thrombotic microangiopathy (elevated LDH, low haptoglobin, thrombocytopenia) 1, 2
• Ophthalmologic damage: bilateral retinal hemorrhages, cotton-wool spots, or papilledema (grade III-IV retinopathy) 1, 2
• Obstetric: severe preeclampsia or eclampsia 1, 2

Hypertensive Urgency (BP ≥180/120 mmHg WITHOUT acute organ damage)

• Manage with oral medications and outpatient follow-up within 2–4 weeks 1, 3
• Hospitalization and IV therapy are not indicated 1, 3

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Blood Pressure Reduction Targets

For Hypertensive Emergency (Standard Approach)

Reduce mean arterial pressure by 20–25% (or systolic BP by ≤25%) within the first hour, then lower to ≤160/100 mmHg over 2–6 hours if stable, and gradually normalize over 24–48 hours. 1, 2

• Critical pitfall: Avoid systolic drops >70 mmHg, which can precipitate cerebral, renal, or coronary ischemia, especially in chronic hypertensives with altered autoregulation 1, 2

Condition-Specific Targets (More Aggressive)

• Aortic dissection: SBP <120 mmHg and HR <60 bpm within 20 minutes 1, 2
• Severe preeclampsia/eclampsia or pheochromocytoma: SBP <140 mmHg within 1 hour 1, 2
• Acute coronary syndrome or pulmonary edema: SBP <140 mmHg immediately 1, 2
• Acute hemorrhagic stroke with SBP ≥220 mmHg: carefully lower to 140–180 mmHg 1, 2
• Acute ischemic stroke with BP >220/120 mmHg: reduce MAP by ~15% over 1 hour 1, 2

For Hypertensive Urgency

• Gradual reduction over 24–48 hours to <160/100 mmHg 1, 3
• Do not rapidly lower BP—this may cause cerebral, renal, or coronary ischemia 1, 3

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First-Line IV Medications for Hypertensive Emergency

Nicardipine (Preferred for Most Emergencies Except Acute Heart Failure)

Nicardipine is the preferred agent because it maintains cerebral blood flow, does not increase intracranial pressure, and allows predictable titration. 1, 2, 4

• Dosing: Start 5 mg/h IV infusion, increase by 2.5 mg/h every 15 minutes to maximum 15 mg/h 1, 4
• Onset: 5–15 minutes; Duration: 30–40 minutes after discontinuation 1, 4
• Preparation: Each 25 mg vial must be diluted with 240 mL compatible IV fluid (D5W, NS, D5W+0.45% NaCl) to yield 0.1 mg/mL concentration 4
• Administration: Use central line or large-bore peripheral IV; change peripheral site every 12 hours to prevent phlebitis 1, 4
• Avoid in: Acute heart failure (causes reflex tachycardia that worsens pulmonary edema) 1, 2

Labetalol (Preferred for Aortic Dissection, Eclampsia, Malignant Hypertension with Renal Involvement)

• Dosing: 10–20 mg IV bolus over 1–2 minutes, repeat or double every 10 minutes (max cumulative 300 mg), OR continuous infusion 2–8 mg/min 1, 2
• Onset: 5–10 minutes; Duration: 3–6 hours 1, 2
• Contraindications: Reactive airway disease, COPD, 2nd/3rd degree heart block, bradycardia, decompensated heart failure 1, 2

Clevidipine (Alternative Rapid-Acting CCB)

• Dosing: Start 1–2 mg/h IV, double every 90 seconds until near target, then increase <2-fold every 5–10 minutes; max 32 mg/h 1, 2
• Onset: 2–4 minutes; Duration: 5–15 minutes 1, 2
• Contraindication: Soy/egg allergy 1, 2

Sodium Nitroprusside (Last-Resort Only)

• Dosing: 0.25–10 µg/kg/min IV infusion 1, 2
• Critical safety: Co-administer thiosulfate when infusion ≥4 µg/kg/min or >30 minutes to prevent cyanide toxicity 1, 2
• Avoid: Should be reserved for failure of other agents due to extreme toxicity 1, 5, 6, 7

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Condition-Specific IV Regimens

Acute Coronary Syndrome / Pulmonary Edema

• First-line: IV nitroglycerin 5–100 µg/min ± labetalol 1, 2
• Avoid: Nicardipine monotherapy (reflex tachycardia worsens ischemia) 1, 2

Aortic Dissection

• First-line: Esmolol loading 500–1000 µg/kg, then infusion 50–200 µg/kg/min BEFORE any vasodilator 1, 2
• Then add: Nitroprusside or nitroglycerin to achieve SBP ≤120 mmHg and HR <60 bpm within 20 minutes 1, 2
• Rationale: Beta-blockade must precede vasodilators to prevent reflex tachycardia 1, 2

Eclampsia / Severe Preeclampsia

• Options: Labetalol, hydralazine, or nicardipine 1, 2
• Absolutely contraindicated: ACE inhibitors, ARBs, sodium nitroprusside 1, 2

Hypertensive Encephalopathy

• First-line: Nicardipine (preserves cerebral perfusion without raising ICP) 1, 2
• Alternative: Labetalol 1, 2

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Oral Medications for Hypertensive Urgency

Preferred Oral Agents

• Captopril 12.5–25 mg PO (caution in volume-depleted patients—risk of abrupt BP fall) 1, 3
• Extended-release nifedipine 30–60 mg PO 1, 3
• Labetalol 200–400 mg PO (avoid in reactive airway disease, heart block, bradycardia) 1, 3

Absolutely Contraindicated

Never use immediate-release nifedipine—it causes unpredictable precipitous BP drops, stroke, and death. 1, 2, 3, 5, 6, 7

Follow-Up

• Arrange outpatient visit within 2–4 weeks 1, 3
• Target BP <130/80 mmHg (or <140/90 mmHg in elderly/frail) within 3 months 1, 3

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Monitoring Requirements for Hypertensive Emergency

• ICU admission with continuous arterial-line BP monitoring (Class I recommendation) 1, 2
• Check BP every 15 minutes for first 2 hours, then every 30 minutes for next 6 hours, then hourly 1, 2
• Monitor for signs of organ hypoperfusion: chest pain, altered mental status, oliguria, acute kidney injury 1, 2
• Serial assessment of target-organ function throughout treatment 1, 2

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Post-Stabilization Management

Screen for Secondary Causes

20–40% of malignant hypertension cases have identifiable secondary etiologies. 1, 2

• Renal artery stenosis, pheochromocytoma, primary aldosteronism, renal parenchymal disease 1, 2
• Screen after stabilization, not during acute crisis 1, 2

Transition to Oral Therapy

• Begin oral regimen 24–48 hours after stabilization 1, 2
• Typical combination: RAS blocker (ACE-I or ARB) + calcium channel blocker + diuretic 1, 2

Long-Term Follow-Up

• Monthly visits until target BP <130/80 mmHg achieved and organ damage regresses 1, 2
• Address medication non-adherence—the most common trigger for hypertensive emergencies 1, 2
• Patients with prior emergency remain at markedly increased cardiovascular and renal risk 1, 2

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Critical Pitfalls to Avoid

• Do not admit asymptomatic severe hypertension without target-organ damage (urgency, not emergency) 1, 2
• Do not use oral agents for hypertensive emergencies—IV therapy is mandatory 1, 2
• Do not use immediate-release nifedipine—risk of precipitous BP fall, stroke, death 1, 2, 3, 5, 6, 7
• Do not rapidly lower BP in hypertensive urgency—gradual reduction is essential 1, 3
• Do not normalize BP acutely in chronic hypertensives—altered autoregulation predisposes to ischemic injury 1, 2
• Do not use hydralazine as first-line (unpredictable response, prolonged duration) 1, 2
• Reserve sodium nitroprusside for last-resort use due to cyanide toxicity 1, 2, 5, 6, 7
• Do not use beta-blockers alone in aortic dissection—always give before vasodilators 1, 2