Drug Information: Nicardipine
Nicardipine is a dihydropyridine calcium channel blocker used primarily for the management of hypertension, including hypertensive emergencies, and angina. It works by selectively inhibiting the influx of calcium ions into vascular smooth muscle and cardiac muscle, leading to vasodilation and a reduction in blood pressure. Its relatively short half-life makes it particularly useful in situations where rapid blood pressure control is needed, allowing for quick titration and adjustment of dosage.
Category
Antihypertensive
Mechanism of Action
Nicardipine is a dihydropyridine calcium channel blocker that primarily affects vascular smooth muscle. Calcium channel blockers, as the name suggests, block voltage-gated L-type calcium channels. These channels are crucial for the influx of calcium into smooth muscle cells. This calcium influx is essential for muscle contraction. By blocking these channels, Nicardipine reduces intracellular calcium concentrations, leading to smooth muscle relaxation and vasodilation. This vasodilation lowers peripheral vascular resistance, which in turn, reduces blood pressure. Nicardipine exhibits greater selectivity for vascular smooth muscle compared to cardiac muscle, making it particularly effective in reducing blood pressure with less direct impact on heart rate and contractility compared to non-dihydropyridine calcium channel blockers like verapamil or diltiazem. The drug’s action leads to decreased systemic vascular resistance without significantly affecting cardiac output at lower doses, making it a suitable choice for managing hypertensive crises and other conditions where blood pressure control is critical.
Clinical Uses
Nicardipine is primarily used in the management of hypertensive emergencies and urgencies, where rapid blood pressure control is necessary to prevent end-organ damage. It is also used for the treatment of chronic hypertension, angina pectoris (both stable and unstable), and to control blood pressure during and after surgery. Furthermore, it can be employed in the management of cerebral vasospasm following subarachnoid hemorrhage, helping to prevent ischemic complications. The drug’s relatively short half-life allows for precise titration, making it ideal for situations requiring close monitoring of blood pressure and quick adjustments to the treatment plan. Due to its selective vasodilation, it is preferred over other agents in situations where minimizing cardiac depression is important.
Dosage
Adults:
* Hypertensive Emergency: IV infusion is typically initiated at 5 mg/hour, which can be increased by 2.5 mg/hour every 5-15 minutes, up to a maximum of 15 mg/hour, until the target blood pressure is achieved. Once the target blood pressure is reached, the infusion rate is reduced to 3 mg/hour.
* Chronic Hypertension/Angina: Oral administration is typically started at 20 mg three times daily. The dosage can be adjusted based on the patient’s response, up to a maximum of 40 mg three times daily.
Pediatrics:
* The safety and efficacy of Nicardipine in pediatric patients have not been definitively established. If used, dosage adjustments are crucial, and administration should be closely monitored. Consult with a pediatric specialist for specific guidance. Typical starting dose (IV) is 0.5-1 mcg/kg/min, titrated to effect.
Indications
* Hypertensive emergencies and urgencies
* Chronic hypertension
* Angina pectoris (stable and unstable)
* Control of blood pressure during and after surgery
* Cerebral vasospasm following subarachnoid hemorrhage
Contraindications
* Hypersensitivity to Nicardipine or any dihydropyridine calcium channel blocker
* Advanced aortic stenosis
* Severe hypotension
* Cardiogenic shock
* Sick sinus syndrome (unless a pacemaker is in place)
* Concomitant use with rifampin (due to significant reduction in nicardipine plasma concentrations)
FAQ
Q: What is Nicardipine used for?
A: Nicardipine is primarily used to treat high blood pressure (hypertension), including hypertensive emergencies, and angina (chest pain). It may also be used to manage blood pressure during and after surgery and to treat cerebral vasospasm following subarachnoid hemorrhage.
Q: How does Nicardipine work?
A: Nicardipine is a calcium channel blocker. It works by relaxing and widening blood vessels, which lowers blood pressure and allows blood to flow more easily to the heart.
Q: What are the common side effects of Nicardipine?
A: Common side effects may include headache, flushing, dizziness, peripheral edema (swelling of ankles and feet), and nausea.
Q: How quickly does Nicardipine lower blood pressure?
A: When administered intravenously, Nicardipine can lower blood pressure relatively quickly, often within minutes. This makes it useful in hypertensive emergencies.
Q: Can Nicardipine be taken during pregnancy?
A: Nicardipine should only be used during pregnancy if the potential benefit justifies the potential risk to the fetus. Consult with a healthcare professional before taking Nicardipine during pregnancy.
Q: Are there any drug interactions with Nicardipine?
A: Yes, Nicardipine can interact with several medications, including beta-blockers, digoxin, cimetidine, and rifampin. It’s important to inform your doctor of all medications you are taking.
Q: What should I do if I miss a dose of oral Nicardipine?
A: If you miss a dose, take it as soon as you remember. However, if it’s almost time for your next dose, skip the missed dose and continue with your regular dosing schedule. Do not double the dose to catch up.
Q: Can Nicardipine cause heart palpitations?
A: While less common, Nicardipine can sometimes cause heart palpitations or an increased heart rate in some individuals. If you experience these symptoms, notify your doctor.
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