Generic Name

Nicardipine

Mechanism

• Selective calcium‑channel blockade: Inhibits L‑type voltage‑gated Ca²⁺ channels in vascular smooth muscle, preventing Ca²⁺ influx.
• Resulting vasodilation: Decreases systemic vascular resistance, lowering arterial blood pressure.
• Reduced myocardial oxygen demand: By lowering afterload, it modestly decreases cardiac workload.
• Preservation of coronary perfusion: Less myocardial depressant effect than non‑dihydropyridine CCBs (e.g., verapamil).

Pharmacokinetics

• Dose form: IV infusion (1 mg/mL in 0.9% saline).
• Absorption: Not applicable (IV).
• Distribution: Wide, high protein binding (~95 % to albumin).
• Metabolism: Hepatic (CYP3A4‑mediated).
• Elimination: Renal (approx. 28 % unchanged), hepatic (72 %).
• Half‑life: ~2 – 4 h (steady‑state 1 – 2 h).
• Brain penetration: Moderate, enabling central vasodilatory actions.

Indications

• Hypertensive emergencies (e.g., uncontrolled BP > 180/110 mm Hg).
• Acute ischemic stroke: Continuous infusion to maintain systolic BP < 140 mm Hg.
• Intra‑operative BP management: In cardiac or neurosurgical procedures.
• Hypertensive encephalopathy: Over‑reliance on its cerebral vasodilatory effect.

Contraindications

• Contraindicated in patients with severe aortic stenosis or advanced heart failure where myocardial calcium influx is required.
• Known hypersensitivity to any CCB or DHP.
• Use with caution in:
• Severe hepatic impairment (metabolism reduction).
• Concomitant use of potent CYP3A4 inhibitors (increased toxicity).
• Patients on potent nitrates (enhanced hypotension).
• Pregnancy: Category C; avoid in first trimester if possible.

Dosing

• Initial rate: 0.3 µg/kg/min IV infusion.
• Titration: Increase by 0.2 µg/kg/min every 15–30 min to achieve target BP.
• Maximum rate: 2.0 µg/kg/min.
• Duration: Typically 6–48 h; may be extended based on clinical response.
• Restarting infusion: If BP rebounds, restart at 0.3 µg/kg/min.

Adverse Effects

• Common
• Reflex tachycardia
• Headache, dizziness
• Peripheral edema
• Facial flushing
• Serious
• Severe hypotension (especially when combined with other antihypertensives)
• Tachyarrhythmias (rare)
• Ocular effects (sudden visual disturbances, angle‑closure glaucoma).
• Drug interactions:
• CYP3A4 inhibitors (ketoconazole, clarithromycin) → increase serum levels.
• CYP3A4 inducers (rifampin, carbamazepine) → decrease efficacy.

Monitoring

• Blood pressure: Every 5–15 min during titration, then hourly.
• Heart rate: Monitor for reflex tachycardia.
• Serum electrolytes: Daily, particularly potassium.
• Liver function: Baseline and repeat as clinically indicated.
• Renal function: Baseline serum creatinine, then twice weekly.
• Neurological status (in stroke): NIH Stroke Scale assessments.

Clinical Pearls

• "Ramp‑up and titrate" rule: Start low to avoid abrupt systemic vasodilation; titrate only after confirming target BP.
• CYP3A4 checks: Prior to infusion, review concurrent meds that may alter nicardipine metabolism; consider dose adjustment if on strong inhibitors.
• Stroke guidelines alignment: Maintain systolic BP 60 bpm.

> *Nicardipine offers a reliable, titratable IV option for managing hypertensive crises with minimal myocardial depressant activity, making it a first‑line choice in stroke care and invasive procedures.*