Nifedipine

Drug Overview

Nifedipine is a commonly used calcium channel blocker primarily indicated for the treatment of hypertension (primary hypertension) and angina pectoris (cardiac ischemia). This medication selectively inhibits calcium ion entry into vascular smooth muscle cells, causing vasodilation, reducing peripheral vascular resistance, thereby lowering blood pressure and improving myocardial blood supply.

Its mechanism of action differs from other classes of antihypertensive drugs, making it particularly suitable for patients who respond poorly to beta-blockers or diuretics. Additionally, nifedipine is used to treat peripheral arterial occlusive disease, alleviating pain or numbness caused by limb ischemia.

Brand Names and Generic Name

The generic name of this medication is Nifedipine. Common brand names include:

• Adalat
• Procardia
• Nifediac

Drug Classification

Nifedipine belongs to the class of "Dihydropyridine calcium channel blockers." This category of drugs is characterized by selective action on vascular smooth muscle, with minimal effects on myocardial contractility and heart rate. Compared to non-dihydropyridines (such as diltiazem), it has a more pronounced vasodilatory effect but may cause more peripheral side effects.

Indications

Main Indications:

• Primary hypertension
• Stable angina pectoris

Other Uses:

• Peripheral arterial disease (intermittent claudication)
• In certain cases, used to control hypertension induced by eclampsia

Common Side Effects

Mild Side Effects:

• Dizziness or headache
• Facial flushing or skin itchiness

Serious Side Effects (Seek medical attention immediately):

• Palpitations or irregular heartbeat
• Shortness of breath or worsening chest pain
• Fainting or altered consciousness

Warnings and Precautions

Contraindications:

• Allergy to nifedipine or its components
• Severe heart failure or cardiomegaly requires caution
• Patients with severe aortic stenosis should avoid use

Pregnancy and Breastfeeding:

• The FDA pregnancy category is C; use during pregnancy should be evaluated by a physician
• The drug may be secreted into breast milk; nursing women should use under medical supervision

Drug Interactions

Nifedipine may interact with the following medications:

• Beta-blockers (e.g., metoprolol): may enhance hypotension or bradycardia
• Statins (e.g., atorvastatin): may increase risk of muscle side effects
• Immunosuppressants (e.g., cyclosporine): may exacerbate hypotension

Consult a healthcare professional before taking herbal medicines or supplements (such as ginkgo biloba extract) to avoid affecting blood pressure control. Consuming grapefruit juice concurrently may increase blood drug levels; it is recommended to avoid it.

Dosage and Administration

Dosage should be adjusted based on the condition:

• For hypertension: usually 20-40 mg daily, divided into doses; sustained-release formulations may be taken once daily
• For angina: initial dose 5-10 mg every 6-8 hours

Swallow the tablets whole; do not chew or break them. They can be taken with or without food, but should be taken consistently at the same time each day to maintain stable blood levels. Sustained-release formulations should not be crushed or dissolved, as this may cause excessive blood pressure reduction.

Missed Dose Management

If a dose is missed, take it as soon as remembered. If it is close to the next scheduled dose, skip the missed dose and resume the regular schedule. Do not double doses to make up for missed ones, to avoid severe reactions such as hypotension.

Overdose Management

Overdose may cause severe hypotension, tachycardia, or syncope. If these symptoms occur, seek immediate medical attention and bring the medication packaging. Emergency measures may include plasma volume expansion, vasopressors, or cardiac monitoring.

 

Frequently Asked Questions

When taking nifedipine, should I pay special attention to meal timing or content?

It is recommended to take nifedipine at a fixed time to maintain stable drug effects. Different formulations (such as regular tablets or sustained-release) may have different instructions; follow your doctor’s advice. Food intake can affect the absorption of regular tablets; it is suggested to take them on an empty stomach or 2 hours after meals. Sustained-release formulations can usually be taken with food. Avoid high-fat meals to reduce gastrointestinal discomfort.

What should I do if I experience lower limb edema while taking nifedipine?

Some patients may experience ankle or calf swelling due to vasodilation. Elevating the legs, reducing standing time, and adopting a low-salt diet may help reduce swelling. If swelling significantly affects daily life, consult your doctor for dose adjustment or medication change. Do not stop the medication on your own.

What precautions should I take when using nifedipine with lipid-lowering drugs (such as statins)?

Combined use may increase the risk of muscle pain or weakness; regular monitoring of creatine phosphokinase (CPK) levels is recommended. Your doctor will adjust the dose based on liver function and overall health. If unexplained muscle pain or dark-colored urine occurs, stop medication and seek medical attention immediately.

What are the risks of suddenly stopping nifedipine?

Sudden discontinuation may cause a rebound phenomenon, leading to a rapid increase in blood pressure and increased risk of cardiovascular events. If medication adjustment is needed, your doctor will gradually reduce the dose and evaluate alternatives. Always discuss with your healthcare team before stopping any medication to avoid self-directed decisions.

Is a sudden drop in blood pressure during exercise related to nifedipine?

This medication may cause orthostatic hypotension due to vasodilation. It is advisable to rest for 15 minutes before exercising and avoid exercising on an empty stomach. Start with low-intensity exercise and gradually increase activity. If dizziness or weakness occurs during exercise, stop immediately and measure blood pressure. Consult your doctor for timing or dosage adjustments if necessary.