What is the effect of Nifedipine (Calcium Channel Blocker)?

From the Guidelines

Nifedipine should not be administered to patients with non-ST-elevation acute coronary syndromes (NSTE-ACS) in the absence of beta-blocker therapy due to its potential to cause harm. This recommendation is based on the 2014 AHA/ACC guideline for the management of patients with non-ST-elevation acute coronary syndromes 1. The guideline states that immediate-release nifedipine should not be administered to patients with NSTE-ACS in the absence of beta-blocker therapy, as it can cause a dose-related increase in mortality in patients with coronary artery disease.

Key Points

• Nifedipine is a calcium channel blocker that works by blocking calcium channels in blood vessel walls, causing them to relax and widen, which reduces blood pressure and improves blood flow to the heart.
• The typical starting dose of nifedipine for hypertension is 30-60 mg once daily of the extended-release formulation, with a maximum daily dose of 90-120 mg.
• For angina, immediate-release nifedipine may be prescribed at 10-20 mg three times daily, though extended-release formulations are generally preferred for most patients.
• Common side effects of nifedipine include headache, flushing, dizziness, and ankle swelling.
• Patients should take nifedipine consistently, with or without food, and should not crush or chew extended-release tablets.
• Grapefruit juice should be avoided as it can increase nifedipine blood levels.
• Elderly patients typically require lower starting doses due to increased sensitivity to the medication's effects.
• Nifedipine should not be stopped abruptly as this could worsen angina symptoms or cause a spike in blood pressure.

Evidence Summary

The evidence for the use of nifedipine in patients with NSTE-ACS is limited, and the majority of studies suggest that it should not be used without concomitant beta-blocker therapy 1. The 2014 AHA/ACC guideline for the management of patients with non-ST-elevation acute coronary syndromes recommends against the use of immediate-release nifedipine in patients with NSTE-ACS in the absence of beta-blocker therapy 1. Therefore, nifedipine should not be used in patients with NSTE-ACS without concomitant beta-blocker therapy.

From the FDA Drug Label

Nifedipine is a calcium ion influx inhibitor (slow-channel blocker or calcium ion antagonist) which inhibits the transmembrane influx of calcium ions into vascular smooth muscle and cardiac muscle. The mechanism by which nifedipine reduces arterial blood pressure involves peripheral arterial vasodilatation and, consequently, a reduction in peripheral vascular resistance Nifedipine is a peripheral arterial vasodilator which acts directly on vascular smooth muscle The reduction in calcium influx by nifedipine causes arterial vasodilation and decreased peripheral vascular resistance which results in reduced arterial blood pressure.

The effect of Nifedipine (Calcium Channel Blocker) is to:

• Reduce arterial blood pressure by causing peripheral arterial vasodilatation and reducing peripheral vascular resistance
• Act as a peripheral arterial vasodilator by directly inhibiting calcium ion influx into vascular smooth muscle
• Decrease peripheral vascular resistance by reducing calcium influx into vascular smooth muscle, resulting in arterial vasodilation 2 2 2

From the Research

Effects of Nifedipine on Cardiovascular Disease

• Nifedipine, a calcium channel blocker, has been shown to be safe and effective in the treatment of various cardiac disorders, including Prinzmetal's variant angina and chronic stable angina 3.
• The efficacy of nifedipine in chronic stable angina stems from an interplay of direct and reflex effects, including a decrease in systemic vascular resistance and myocardial oxygen demand 3.
• Nifedipine may also be of value in the therapy of unstable angina, acute myocardial infarction, and hypertension, as well as in the protection of the myocardium at risk during open heart surgery 3.

Effects of Nifedipine on Hypertension

• Modified-release formulations of nifedipine are effective antihypertensive therapies and are generally well tolerated 4.
• Nifedipine gastrointestinal therapeutic system (GITS) and nifedipine retard have been shown to have beneficial effects on the overall incidence of major cardiovascular events in patients with hypertension 4, 5.
• The extended-release formulation of nifedipine given once daily provides a relatively constant concentration profile and has been proven to be effective in reducing blood pressure values 5.

Effects of Nifedipine on Angina Pectoris

• Modified-release formulations of nifedipine are effective antianginal therapies and are generally well tolerated 4.
• Nifedipine GITS has been shown to reduce the need for coronary procedures in patients with coronary artery disease 4.
• Nifedipine has been demonstrated to increase exercise tolerance by lowering the heart rate-blood pressure product in patients with chronic angina 3.

Comparison with Other Treatments

• Nifedipine GITS and amlodipine have been shown to be comparably safe and effective treatment options in patients with mild-to-moderate essential hypertension 6.
• Nifedipine has been compared to diuretics in the International Nifedipine gastrointestinal therapeutic system Study: Intervention as a Goal in Hypertension Treatment (INSIGHT) study, and was found to confer cardiovascular protection as effectively as diuretics in high-risk patients, with a smaller incidence of adverse metabolic consequences 5.