Effective Treatment Response to Nicardipine in Hypertensive Emergency
In a hypertensive emergency, treatment with nicardipine (Cardene) drip is considered effective when the mean arterial pressure (MAP) decreases by 20-25% within several hours. 1
Target Blood Pressure Reduction by Clinical Presentation
The appropriate reduction in MAP varies based on the specific hypertensive emergency:
- Malignant hypertension with or without thrombotic microangiopathy or acute renal failure: MAP reduction of 20-25% over several hours 1
- Hypertensive encephalopathy: Immediate MAP reduction of 20-25% 1
- Acute ischemic stroke with BP >220/120 mmHg: MAP reduction of 15% within 1 hour 1
- Acute ischemic stroke with indication for thrombolytic therapy: MAP reduction of 15% within 1 hour 1
Caution with Blood Pressure Reduction
- Excessive BP reduction (>50% decrease in MAP) has been associated with ischemic stroke and death 1
- In a study of hypertensive emergencies, 57% of patients were treated excessively (MAP reduction beyond 25% at the end of the two-hour acute phase) 2
- Patients receiving nicardipine had a greater risk of excessive MAP reduction at two hours compared to other antihypertensive agents 2
Nicardipine Dosing and Response
- Initial dosing typically starts at 5 mg/h, increasing every 5 minutes by 2.5 mg/h to a maximum of 15 mg/h 1
- Higher infusion rates (5-15 mg/h) produce therapeutic responses more rapidly 3
- For severe hypertension, the mean time to therapeutic response (defined as diastolic BP ≤95 mmHg or ≥25 mmHg decrease and systolic BP ≤160 mmHg) is approximately 77 minutes 3
- The average maintenance dose is typically 8.0 mg/h for severe hypertension 3
Monitoring and Adjustment
- Continuous monitoring of BP and target organ damage in an intensive care unit is recommended for patients with hypertensive emergencies 1
- Titrate nicardipine to achieve the target MAP reduction based on the specific clinical presentation 1
- After the initial reduction, if stable, aim to reduce BP to 160/100 mmHg within the next 2-6 hours 1
- Then cautiously reduce to normal during the following 24-48 hours 1
Clinical Considerations
- Nicardipine is an effective alternative to labetalol in most hypertensive emergencies 1
- In a recent study comparing nicardipine to clevidipine, nicardipine achieved sustained systolic BP control (<160 mmHg at 2-6 hours) more effectively (89.2% vs 73.2%) 4
- Patients are often volume depleted due to pressure natriuresis; intravenous saline may be needed to correct precipitous BP falls 1
- Side effects of nicardipine include headache, flushing, and phlebitis at the infusion site 5
Remember that the specific target for BP reduction should be based on the underlying condition causing the hypertensive emergency, with most conditions requiring a MAP reduction of 20-25%, while acute ischemic stroke requires a more conservative 15% reduction 1.