Advanced Anti- Hypertensive Therapy in the ICU

Intravenous Antihypertensive Options for Refractory Acute Hypertension

When an IV nicardipine infusion (titrated up to its usual ceiling of ≈ 15 mg/h) plus intermittent IV hydralazine fails to achieve the desired blood-pressure target, the next steps are to add—or switch to—agents from different pharmacologic classes. Continuous arterial-line monitoring is essential to avoid precipitous drops in MAP.

Class / Agent	Typical ICU Dosing & Key Pearls	Cautions in This Patient (CKD stage 3, diabetes)
β-Blocker (α1-blocking) Labetalol	• 20 mg IV bolus → repeat 20–80 mg q10 min (max 300 mg) • Continuous 0.5–2 mg / min	Avoid if acute HF, bronchospasm, brady-arrhythmia; synergistic with nicardipine for “balanced” control
Ultra–short-acting β-Blocker Esmolol	500 µg/kg IV load over 1 min → 50–300 µg/kg/min	Ideal for tachy-adrenergic surges; titrate if HR < 60 bpm
Alternative dihydropyridine CCB Clevidipine	1–2 mg/h → double q5–10 min (max 32 mg/h)	Rapid offset (~5 min); lipid emulsion—avoid if TG > 400 mg/dL or egg/soy allergy
Direct arterial/venous vasodilator Sodium Nitroprusside	0.3 µg/kg/min → titrate (max 10 µg/kg/min)	Cyanide/thiocyanate accumulation with > 48 h use or renal failure—limit duration, monitor levels
Venodilator (coronary-friendly) Nitroglycerin	5 µg/min → ↑ by 5–10 µg/min q5–10 min (typ max 200 µg/min)	Best when myocardial ischemia or pulmonary edema present; tachyphylaxis after 24–48 h
Dopamine-1 agonist Fenoldopam	0.1 µg/kg/min → titrate q15 min (max 1.6 µg/kg/min)	Improves renal perfusion & diuresis; watch reflex tachycardia, glaucoma
IV ACE-I Enalaprilat	0.625–1.25 mg IV q6 h (max 5 mg)	Slower onset (15–30 min); monitor K+ & creatinine
α-Blocker Phentolamine	5 mg IV → repeat to total 15 mg	Reserve for catecholamine excess (pheochromocytoma, cocaine)
Adjuncts	• Loop diuretic (furosemide 20–40 mg IV) for volume overload • Sedation/analgesia (dexmedetomidine, fentanyl) to blunt sympathetic drive	Account for volume status, renal function, neurologic monitoring needs

Practical Escalation Strategy

1. Optimize nicardipine first (up-titrate to 15 mg/h).
2. Add a β-blocker—labetalol bolus or esmolol infusion—if tachycardia or high cardiac output contributes.
3. Switch to—or layer—clevidipine if BP remains labile despite maximal nicardipine.
4. Introduce nitroprusside or nitroglycerin for rapid afterload reduction (nitroprusside) or when myocardial ischemia/pulmonary edema coexist (nitroglycerin).
5. Consider fenoldopam instead of nitroprusside in CKD to avoid cyanide toxicity and preserve renal blood flow.
6. Use enalaprilat as an adjunct when renin–angiotensin activation is suspected and BP control remains unsatisfactory.
7. Search for reversible drivers (pain, agitation, fluid overload, drug interactions, missed home meds).

Monitoring & Safety

• Continuous arterial BP and cardiac telemetry.
• Serum creatinine & electrolytes q6–12 h (especially K⁺ with ACE-I / ARB, Na⁺/Cr with nitroprusside).
• Avoid overshoot hypotension—target a 10–20 % MAP reduction in the first hour, then gradual normalization over 24 h unless aortic dissection, eclampsia, or intracranial pathology mandates faster control.