What medications can be used for acute control of hypertension after administering clonidine and captopril?

Third-Line Agents for Acute Hypertension Control

After clonidine and captopril have been administered, intravenous nicardipine (5-15 mg/h) or labetalol (0.25-0.5 mg/kg IV bolus followed by 2-4 mg/min infusion) should be initiated for continued acute blood pressure control in hypertensive emergencies. 1

Preferred Intravenous Options

Nicardipine (Dihydropyridine Calcium Channel Blocker)

• Start at 5 mg/h IV infusion, increase every 15 minutes by 2.5 mg/h until goal BP is reached, then decrease to 3 mg/h for maintenance 1
• Onset of action: 5-15 minutes with duration of 30-40 minutes 1
• Particularly effective in acute renal failure, eclampsia/preeclampsia, and perioperative hypertension 1
• Contraindicated in liver failure 1
• Common adverse effects include headache and reflex tachycardia 1

Labetalol (Combined Alpha and Beta Blocker)

• Dose: 0.25-0.5 mg/kg IV bolus, followed by 2-4 mg/min continuous infusion until goal BP reached, then 5-20 mg/h maintenance 1
• Onset: 5-10 minutes with duration of 3-6 hours 1
• First-line choice for most hypertensive emergencies due to combined alpha and beta-blocking properties 2
• Contraindicated in 2nd or 3rd degree AV block, systolic heart failure, asthma, and bradycardia 1
• Risk of bronchoconstriction and fetal bradycardia (cumulative dose should not exceed 800 mg/24h in pregnancy) 1

Alternative Intravenous Agents

Clevidipine (Ultra-Short Acting Calcium Channel Blocker)

• Start at 2 mg/h IV infusion, increase every 2 minutes by 2 mg/h until goal BP 1
• Onset: 2-3 minutes with duration of 5-15 minutes 1
• Excellent for situations requiring rapid titration and precise control 1

Esmolol (Ultra-Short Acting Beta Blocker)

• Loading dose: 500-1000 mcg/kg/min over 1 minute, followed by 50 mcg/kg/min infusion 1
• Particularly useful in acute aortic dissection when combined with vasodilators 1
• Contraindicated in concurrent beta-blocker therapy, bradycardia, or decompensated heart failure 1

Sodium Nitroprusside (Direct Vasodilator)

• Start at 0.3 mcg/kg/min, increase by 0.5 mcg/kg/min every 5 minutes until goal BP (maximum 10 mcg/kg/min) 1
• Immediate onset with 1-2 minute duration 1
• Drug of choice for acute cardiogenic pulmonary edema 1
• Major caveat: Risk of cyanide intoxication; contraindicated in liver/kidney failure 1
• Should be used with caution in patients with impaired cerebral flow 3

Clinical Context and Decision-Making

If Patient Has Specific Comorbidities:

• Acute coronary syndrome: Nitroglycerin (5-200 mcg/min) or labetalol preferred 1
• Acute pulmonary edema: Nitroprusside or nitroglycerin (avoid beta blockers) 1
• Acute aortic dissection: Esmolol combined with nitroprusside or clevidipine to achieve SBP ≤120 mmHg within 20 minutes 1
• Acute renal failure: Clevidipine, fenoldopam, or nicardipine 1
• Eclampsia/preeclampsia: Labetalol or nicardipine (avoid nitroprusside due to fetal cyanide toxicity risk) 1

Blood Pressure Reduction Targets:

• Reduce mean arterial pressure by 20-25% over the first several hours 4
• Avoid excessive reduction (>50% decrease in MAP) as this increases risk of ischemic stroke and death 4
• Target SBP <160/100 mmHg within 2-6 hours after initial reduction 2

Critical Pitfalls to Avoid

• Do not use beta blockers alone as vasodilators in aortic dissection - always provide beta blockade first to prevent reflex tachycardia 1
• Avoid nitroprusside in pregnancy due to fetal cyanide toxicity risk 1
• Monitor for excessive BP reduction - a 28% reduction in systolic BP exceeds recommended targets and requires slowing of therapy 4
• Plan transition to oral therapy once patient stabilizes - do not abruptly discontinue IV agents without bridging 4
• Avoid labetalol in pheochromocytoma as it may paradoxically accelerate hypertension 1