Is 40cc per hour of nicardipine an overdose?

Is 40cc per hour nicardipine an overdose?

Yes, 40 mg/hour of nicardipine is a dangerous overdose—the absolute maximum recommended dose is 15 mg/hour, and exceeding this significantly increases the risk of severe hypotension, reflex tachycardia, and end-organ hypoperfusion. 1, 2

Understanding the Dosing Error

The question appears to reference "40cc per hour," which likely means 40 mg/hour if using standard nicardipine concentrations. This represents nearly 3 times the maximum recommended dose and constitutes a critical medication error. 1, 2

Standard Nicardipine Dosing Protocol

• Initial dose: Start at 5 mg/hour IV infusion 1, 2, 3
• Titration: Increase by 2.5 mg/hour every 5-15 minutes based on blood pressure response 1, 2, 3
• Absolute maximum: 15 mg/hour—this ceiling applies to all clinical scenarios regardless of severity 1, 2
• Maintenance dose: Once blood pressure goal is achieved, reduce to 3 mg/hour 3

Why 40 mg/hour is Dangerous

Cardiovascular Risks

• Profound hypotension: Doses exceeding 15 mg/hour cause excessive vasodilation that can lead to systemic hypotension and end-organ hypoperfusion 1, 3
• Reflex tachycardia: Higher doses increase the incidence of compensatory tachycardia (baseline incidence 4% at therapeutic doses) 3
• Neurologic deterioration: In acute intracerebral hemorrhage patients, higher maximum nicardipine doses were independently associated with early neurologic deterioration (OR 1.25 per 1 mg/hour increase) 4

Clinical Context from Overdose Literature

• While specific nicardipine overdose data is limited, calcium channel blocker overdoses (including nifedipine at 900 mg) have resulted in profound hypotension, sinus and atrioventricular node dysfunction, and hyperglycemia 5
• These effects required aggressive treatment with IV fluids, calcium, and vasopressors 5

Immediate Management if This Dose Was Administered

Step 1: Stop the Infusion Immediately

• Discontinue nicardipine infusion right away 1
• The offset of action occurs within 30-40 minutes after discontinuation, regardless of infusion duration 2, 3

Step 2: Intensive Hemodynamic Monitoring

• Check blood pressure every 5 minutes initially, then every 15 minutes once stabilizing 1, 2
• Continuous cardiac monitoring for dysrhythmias and heart rate changes 2
• Monitor for signs of end-organ hypoperfusion (altered mental status, decreased urine output, chest pain) 3

Step 3: Supportive Treatment for Hypotension

• IV fluid resuscitation: Aggressive crystalloid administration 5
• Calcium administration: Calcium chloride 2000 mg IV or calcium gluconate 6000 mg IV to counteract calcium channel blockade 6
• Vasopressor support: If hypotension persists despite fluids and calcium, initiate dopamine or norepinephrine 5

Step 4: Assess for Complications

• Check serum glucose (calcium channel blocker overdose can cause hyperglycemia) 5
• Obtain ECG to evaluate for conduction abnormalities 5
• Monitor renal function and urine output 3

Critical Safety Considerations

• Never exceed 15 mg/hour: This is an absolute maximum supported by all major guidelines from the American Heart Association and American College of Cardiology 1, 2
• If blood pressure remains uncontrolled at 15 mg/hour: Switch to alternative agents like sodium nitroprusside or labetalol rather than exceeding the maximum dose 1, 2
• Special populations at higher risk: Elderly patients, those with hepatic impairment, and patients with cerebrovascular disease are particularly vulnerable to excessive blood pressure reduction 3

Common Pitfalls to Avoid

• Confusing concentration with dose: Ensure clarity on whether orders specify mg/hour versus mL/hour based on the specific concentration being used 1
• Assuming higher doses are needed for refractory hypertension: If 15 mg/hour is insufficient, the appropriate response is to add or switch agents, not exceed the maximum dose 1, 2
• Failing to reduce to maintenance dosing: Once blood pressure goals are achieved, the infusion should be decreased to 3 mg/hour, not continued at high rates 3