From the Guidelines
Nifedipine, a calcium channel blocker, has a complex effect on the body, primarily causing vasodilation, which can lead to decreased blood pressure, and can be beneficial in controlling ischemia-related symptoms, but its use must be cautious, especially in patients without concomitant beta blockade, due to increased adverse potential.
Effects of Nifedipine
- Vasodilation: Nifedipine has the most peripheral arterial dilatory effects, which can help decrease myocardial oxygen demand and improve myocardial flow 1.
- Decreased Myocardial Oxygen Demand: By reducing afterload, contractility, and heart rate, nifedipine can decrease myocardial oxygen demand, which can be beneficial in patients with unstable angina or non-ST-elevation myocardial infarction (UA/NSTEMI) 1.
- Improved Myocardial Flow: Nifedipine's coronary dilatory properties can improve myocardial flow, which can help relieve or prevent signs and symptoms of ischemia 1.
Side Effects and Precautions
- Hypotension: Nifedipine can cause hypotension, which can be a major side effect, especially in patients without concomitant beta blockade 1.
- Increased Adverse Potential: Rapid-release, short-acting dihydropyridines like nifedipine must be avoided in the absence of concomitant beta blockade due to increased adverse potential 1.
- Contraindications: Nifedipine should be avoided in patients with pulmonary edema or evidence of severe left ventricular (LV) dysfunction 1.
Clinical Use
- UA/NSTEMI: Nifedipine may be used to control ongoing or recurring ischemia-related symptoms in patients who already are receiving adequate doses of nitrates and beta blockers, or in patients who are unable to tolerate adequate doses of one or both of these agents 1.
- Variant Angina: Nifedipine can be used to control symptoms in patients with variant angina 1.
- Hypertension: Nifedipine can be used for the management of hypertension in patients with recurrent UA 1.
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 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 is to reduce arterial blood pressure by causing peripheral arterial vasodilatation and decreasing peripheral vascular resistance. This is achieved by inhibiting calcium ion influx into vascular smooth muscle and cardiac muscle, resulting in arterial vasodilation. 2
From the Research
Effects of Nifedipine on Blood Pressure
- Nifedipine is a dihydropyridine calcium-channel blocker that lowers blood pressure and improves symptoms of angina 3.
- The drug has been shown to produce a rapid and vigorous vasodilating effect on the peripheral vasculature, making it effective in treating hypertensive emergencies 4.
- Studies have demonstrated that nifedipine can reduce blood pressure in patients with hypertension, with a median reduction in systolic blood pressure of -10 mmHg 5.
Safety and Efficacy of Nifedipine
- Despite concerns about the safety of immediate-release nifedipine, studies have found that the incidence of adverse events such as myocardial infarction, arrhythmias, and stroke may be lower than previously believed 6, 5.
- However, nifedipine can cause clinically significant hypotension, with 27% of patients experiencing a significant reduction in blood pressure or requiring vasopressor support 5.
- The drug has also been associated with new-onset arrhythmia and myocardial injury in some patients 5.
Mechanism of Action
- Nifedipine exerts its effect by calcium channel blockade and nitric oxide production, but it also has a previously uncharacterized action on central synaptic transmission that may partially explain its side effects 7.
- The drug has been shown to facilitate neurotransmitter release independently of calcium channels, which may be a useful tool for targeting the release process but also raises caution for its use as an L-type calcium channel blocker 7.