Nicardipine Infusion Protocol for Hypertensive Emergency
Start nicardipine at 5 mg/hr IV and titrate by 2.5 mg/hr every 5–15 minutes to a maximum of 15 mg/hr until the desired blood pressure reduction is achieved, targeting a 10–15% reduction in mean arterial pressure within the first hour. 1, 2
Initial Dosing and Titration
Begin at 5 mg/hr through a central line or large peripheral vein; this is the standard starting dose for all hypertensive emergencies. 1, 3
Titrate by 2.5 mg/hr increments every 5–15 minutes based on clinical urgency: use 5-minute intervals when rapid control is required, or 15-minute intervals for more gradual reduction. 1, 2
Maximum dose is 15 mg/hr; if blood pressure remains uncontrolled at this ceiling, switch to sodium nitroprusside (0.3–0.5 µg/kg/min) or consider adding labetalol. 1, 2
Onset of action occurs within 5–15 minutes, with therapeutic blood pressure reduction typically achieved within this timeframe; the offset after discontinuation is 30–40 minutes regardless of infusion duration. 1, 4, 5
Blood Pressure Targets
First hour: Reduce mean arterial pressure by 10–15% (maximum 25%) to avoid precipitating cerebral, renal, or coronary ischemia—especially critical in patients with chronic hypertension who have altered autoregulation. 1, 2
Hours 24–48: Gradually normalize blood pressure; never drop systolic pressure >70 mmHg acutely as this precipitates stroke, myocardial infarction, or acute kidney injury. 1, 2
Condition-Specific Targets
| Clinical Scenario | Target Blood Pressure | Timeframe |
|---|---|---|
| Acute ischemic stroke (pre-thrombolytic) | <185/110 mmHg | Before rtPA administration |
| Acute ischemic stroke (post-thrombolytic) | <180–185/105–110 mmHg | Maintain for ≥24 hours |
| Acute intracerebral hemorrhage | 140–180 mmHg systolic | Within 6 hours |
| Acute aortic dissection | <120 mmHg systolic (beta-blockade first) | Within 20 minutes |
| Acute coronary syndrome/pulmonary edema | <140 mmHg systolic | Immediately |
| Eclampsia/preeclampsia | <140 mmHg systolic | Within first hour |
Maintenance Dosing
Once the target blood pressure is achieved, reduce to 3 mg/hr as the maintenance infusion rate; this lower rate sustains control while minimizing side effects. 1
Sustained blood pressure control at a constant infusion rate is maintained for 4–6 hours during continuous infusion; the drug continues working throughout this period without tachyphylaxis. 1, 4
Monitoring Requirements
Continuous arterial-line monitoring in the ICU is a Class I recommendation for all hypertensive emergencies. 1, 2
Check blood pressure every 15 minutes for the first 2 hours, then every 30 minutes for the next 6 hours, then hourly for 16 hours (especially critical in post-thrombolytic stroke patients). 1
Monitor heart rate continuously; nicardipine typically increases heart rate by approximately 10 beats/minute due to reflex tachycardia, though this does not correlate with plasma levels. 1, 4
Administration and Site Management
Administer through a central line or large peripheral vein; avoid small veins such as those on the dorsum of the hand or wrist to reduce thrombophlebitis risk. 3
Change the infusion site every 12 hours when using peripheral access; phlebitis occurred in 7/18 patients after ≥14 hours at a single site in early studies, but this complication was eliminated by routine site rotation. 3, 4, 5
Single-dose vials (25 mg/10 mL) must be diluted before use; premixed flexible containers (0.1 mg/mL or 0.2 mg/mL) are ready to infuse. 3
Management of Adverse Effects
If hypotension or marked tachycardia develops, stop the infusion immediately; nicardipine's offset occurs within 30–40 minutes. 1, 3
Once hemodynamics stabilize, restart at 3–5 mg/hr and titrate more cautiously. 1
Common side effects include headache (13%), hypotension (5%), tachycardia (4%), nausea/vomiting (4%), and flushing; these are generally mild and related to vasodilation. 1, 3, 4
Contraindications and Precautions
Absolute contraindication: Advanced aortic stenosis—nicardipine can precipitate severe hypotension and cardiovascular collapse in this population. 2, 3
Avoid in acute heart failure/pulmonary edema as monotherapy; reflex tachycardia can worsen myocardial oxygen demand—use nitroglycerin or nitroprusside instead. 1, 2
Aortic dissection requires beta-blockade first (esmolol 500–1000 µg/kg loading, then 50–200 µg/kg/min) before adding nicardipine to prevent reflex tachycardia that increases aortic shear stress. 1, 2
Exercise extreme caution in acute stroke patients to avoid systemic hypotension; in ischemic stroke, blood pressure reduction within the first 5–7 days is associated with adverse neurological outcomes. 1
No dose adjustment required in elderly patients or those with renal impairment, though closer monitoring is prudent. 1
Drug Interactions
Cimetidine increases nicardipine plasma levels; monitor blood pressure more frequently if co-administered. 1, 3
Nicardipine inhibits CYP3A4 and can significantly elevate cyclosporine and tacrolimus levels; monitor immunosuppressant trough levels closely when co-administering. 1, 3
When Nicardipine Fails or Is Inappropriate
Refractory hypertension at 15 mg/hr: Switch to sodium nitroprusside (0.3–0.5 µg/kg/min, increase by 0.5 µg/kg/min every 5 min to max 10 µg/kg/min); co-administer thiosulfate when infusion ≥4 µg/kg/min or >30 minutes to prevent cyanide toxicity. 1, 2
Alternative: Labetalol 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—but avoid in reactive airway disease, COPD, heart block, bradycardia, or decompensated heart failure. 1, 2
Critical Pitfalls to Avoid
Do not use nicardipine for hypertensive urgency (severe BP elevation without organ damage)—IV agents are reserved exclusively for emergencies; oral therapy is appropriate for urgencies. 2, 6
Do not rapidly normalize blood pressure in chronic hypertensives; altered cerebral autoregulation makes acute normalization dangerous and can precipitate stroke. 1, 2
Do not use immediate-release nifedipine—it causes unpredictable precipitous drops, reflex tachycardia, stroke, and death. 1, 2
Nicardipine is not a beta-blocker substitute and provides no protection against abrupt beta-blocker withdrawal; withdraw beta-blockers gradually. 3
Do not assume symptom absence equals absence of organ damage; perform focused neurologic exam, fundoscopy (looking for bilateral retinal hemorrhages, cotton-wool spots, papilledema), cardiac assessment, and laboratory screening (CBC, creatinine, LDH, haptoglobin, troponin, urinalysis) before classifying as urgency. 2