What is the recommended initial dose of Nicardipine (calcium channel blocker) for treating hypertension?

Nicardipine Dosing for Hypertension

For oral nicardipine in chronic hypertension, start at 20 mg three times daily and titrate up to 20-40 mg three times daily as needed; for intravenous nicardipine in hypertensive emergencies, start at 5 mg/hr and titrate by 2.5 mg/hr every 5-15 minutes up to a maximum of 15 mg/hr. 1, 2

Oral Nicardipine Dosing (Chronic Hypertension)

Initial Dose

• Begin with 20 mg three times daily 2
• Allow at least 3 days between dose increases to achieve steady-state plasma concentrations 2

Titration and Maintenance

• Effective dose range: 20-40 mg three times daily 2, 3, 4
• Maximum blood pressure lowering occurs 1-2 hours after dosing 2
• Measure blood pressure at trough (8 hours after dosing) to assess adequacy of response 2
• Also measure blood pressure 1-2 hours after dosing during initiation to capture peak effects 2

Special Populations

• Renal insufficiency: Start with 20 mg three times daily with careful titration 2, 5
• Hepatic insufficiency: Start with 20 mg twice daily (note the reduced frequency) with individual titration 2
• Elderly patients: The standard 20 mg three times daily starting dose is effective and safe, including in those with renal dysfunction 5

Intravenous Nicardipine Dosing (Hypertensive Emergencies)

Initial Dose and Titration

• Start at 5 mg/hr IV infusion 1, 6
• Increase by 2.5 mg/hr every 5-15 minutes 1, 6
• Maximum dose: 15 mg/hr 1, 6
• Onset of action: 5-15 minutes 1
• Duration of action after discontinuation: 30-40 minutes 1

Blood Pressure Targets

• Aim for 10-15% reduction in blood pressure initially 1
• In hypertensive emergencies, continuous infusion of short-acting titratable agents like nicardipine is preferred to prevent target organ damage 6

Monitoring Requirements

• During titration: Check blood pressure every 15 minutes 1
• First 2 hours: Every 15 minutes 1
• Next 6 hours: Every 30 minutes 1
• Subsequent 16 hours: Hourly 1

Conversion from IV to Oral

• Oral 30 mg three times daily is equivalent to IV 1.2 mg/hr 1
• Oral 40 mg three times daily is equivalent to IV 2.2 mg/hr 1

Clinical Context and Efficacy

Blood Pressure Reduction

• In clinical trials, nicardipine 20-40 mg three times daily reduced supine systolic blood pressure by 10-15 mm Hg and diastolic blood pressure by 10 mm Hg 4
• In severe hypertension (diastolic >120 mm Hg), IV nicardipine at 4-15 mg/hr achieved therapeutic goals (diastolic ≤95 mm Hg or >25 mm Hg reduction) rapidly 7

Combination Therapy

• Nicardipine can be safely combined with beta-blockers, nitrates, and thiazide diuretics 2
• As a dihydropyridine calcium channel blocker, it is recommended as first-line therapy for hypertension alongside ACE inhibitors, ARBs, and thiazide-like diuretics 6

Common Pitfalls and Safety Considerations

Adverse Effects (Dose-Related)

• Most common: Flushing (12-28%), headache (8-16%), peripheral edema (5-27%) 3, 8, 4
• These are vasodilation-related and occur more frequently at higher doses 8
• Most adverse effects occur in the first 3 months of treatment 8

Special Cautions

• Acute stroke patients: Exercise extreme caution to avoid systemic hypotension, as blood pressure reduction within the first 5-7 days is associated with adverse neurological outcomes 1
• IV administration: Local phlebitis can occur after ≥14 hours of infusion at a single site; rotate sites to prevent this 7
• Heart rate: Expect an increase of approximately 10 beats/minute with IV nicardipine 7

Drug Interactions

• Nicardipine inhibits CYP3A4, requiring close monitoring of cyclosporine and tacrolimus levels in transplant patients 1
• Cimetidine increases nicardipine levels and requires careful monitoring if used concomitantly 1