Action and Spectrum

Actions and spectrum:

nifedipine is a calcium channel blocker with primarily vasodilating activity. It works by blocking the influx of calcium ions into smooth muscle cells, leading to relaxation and dilation of the arterial smooth muscles. This results in a decrease in peripheral vascular resistance and blood pressure.

In addition to its anti-hypertensive effects, nifedipine also has antianginal effects, making it useful in the treatment of angina pectoris. nifedipine also has tocolytic effects, which means it can relax the smooth muscles of the uterus and delay or prevent preterm labor in pregnant women.

Drug Interaction

Adverse Reaction

Frequency defined:

>10%

Nausea (11%)

Heartburn (11%)

Headache (10-23%)

Dizziness (23-27%)

Flushing (23-27%)

Peripheral edema (10-30%)

1-10%

Urticaria (2%)

Constipation (<2%)

Pruritus (2%)

Chest pain (<2%)

Hypotension (5%)

Cough (6%)

Palpitations (6%)

Dyspnea (6%)

Wheezing (6%)

Nervousness (7%)

Mood change (7%)

Muscle cramps (8%)

Frequency undefined:

Gingival hyperplasia

Erectile dysfunction

Agranulocytosis 

Post marketing Reports

Photosensitivity reactions

erythema multiforme

Stevens-Johnson syndrome

Acute generalized exanthematous pustulosis

Black Box Warning

Contraindication / Caution

Contraindication/Caution

Contraindication

• Hypersensitivity to nifedipine or any other component of the formulation.
• Pregnancy, especially during the first trimester, or when using the immediate-release formulation for the treatment of hypertension.
• Severe hypotension (systolic blood pressure <90 mmHg).
• Cardiogenic shock.
• Obstruction of the left ventricle (e.g., aortic stenosis).
• Acute myocardial infarction and pulmonary congestion.
• Concurrent use of strong CYP3A4 inhibitors (e.g., ketoconazole, itraconazole, clarithromycin, ritonavir).
• Concurrent use of rifampin or other CYP3A4 inducers.

Caution

• Hypotension: nifedipine can cause a drop in blood pressure, which can be severe in patients with low blood pressure or those taking antihypertensive medications.
• Heart Failure: nifedipine may worsen the symptoms of heart failure in patients with underlying heart disease.
• Hepatic Impairment: nifedipine is metabolized by the liver, and its clearance may be reduced in patients with liver dysfunction, leading to an increased risk of adverse effects.
• Renal Impairment: nifedipine is eliminated by the kidneys, and its clearance may be reduced in patients with renal dysfunction, leading to an increased risk of adverse effects.
• Elderly Patients: Elderly patients may be more sensitive to the effects of nifedipine, and dose adjustments may be required.
• Pregnancy and Breastfeeding: nifedipine should be used with caution in pregnant or breastfeeding women, as its safety has not been established in these populations.
• Hypertrophic Cardiomyopathy: nifedipine may worsen the symptoms of cardiomyopathy, which is characterized by the thickening of the heart muscle. 

Comorbidities

• Heart failure: nifedipine can cause a decrease in blood pressure, which can exacerbate heart failure in patients with left ventricular dysfunction.
• Liver disease: nifedipine is metabolized by the liver, and patients with liver disease may be more susceptible to adverse effects.
• Renal impairment: nifedipine is eliminated through the kidneys, and patients with renal impairment may require dose adjustments to avoid adverse effects.
• Pregnancy: nifedipine is classified as pregnancy category C and in pregnant patients should be used with caution.
• Breastfeeding: nifedipine is excreted in breast milk, and caution should be exercised in nursing mothers.
• Elderly patients: may be more susceptible to adverse effects of nifedipine and may require dose adjustments to avoid adverse effects.
• Patients with aortic stenosis: nifedipine can cause hypotension, which may worsen symptoms in patients with aortic stenosis.

Pregnancy / Lactation

Pregnancy consideration: pregnancy category C

Lactation: should be used with caution as it is excreted in breast milk. 

Pregnancy category:

• Category A: Satisfactory and well-controlled studies show no risk to the fetus in the first or later trimester.
• Category B: There is no evidence of risk to the fetus found in animal reproduction studies and there are not enough studies on pregnant women.
• Category C: Adverse effects on the fetus found with evidence in animal reproduction studies and no adequate evidence for an effect in humans, care must be taken for potential risks in pregnant women
• Category D: There is adequate data available with sufficient evidence of human fetal risk from various platforms, but despite potential risks may be used only in emergency cases for potential benefits.
• Category X: Drugs listed in this category outweigh risks over benefits These category drugs should be prohibited for pregnant women.
• Category N: There is no data available for the drug under this category.

Pharmacology

Pharmacology

nifedipine is a dihydropyridine calcium channel blocker (CCB) that inhibits the influx of calcium ions through L-type voltage-gated calcium channels in cardiac muscle and vascular smooth muscle. It has a short duration of action.

nifedipine acts on peripheral blood vessels, reducing peripheral vascular resistance and causing vasodilation. This leads to a decrease in systemic arterial pressure, an increase in heart rate, and an increase in cardiac output. nifedipine also has a coronary vasodilatory effect, which can increase coronary blood flow.

Pharmacodynamics

nifedipine is a dihydropyridine calcium channel blocker that acts primarily on vascular smooth muscle, leading to the relaxation of peripheral arterioles and a reduction in systemic vascular resistance. It inhibits the influx of calcium ions through L-type calcium channels in the plasma membrane of cardiac and smooth muscle cells, leading to vasodilation and a decrease in myocardial oxygen demand. It selectively dilates coronary arteries and arterioles, both in normal and ischemic regions and is a potent arterial vasodilator.

In addition, it has a negative inotropic effect on the cardiac muscle and can decrease the conduction velocity of the atrioventricular node. nifedipine also has effects on other tissues, including the myocardium, where it can decrease contractility and prolong the action potential. It has also been shown to have anti-inflammatory and immunomodulatory effects in various cell types, including macrophages and lymphocytes.

pharmacokinetics

nifedipine is rapidly absorbed from the gastrointestinal tract, with peak plasma concentrations occurring 1-2 hours after oral administration. The drug gets metabolized in the liver by the cytochrome P450 enzyme system, primarily CYP3A4, and excreted in the urine and feces. The half-life of nifedipine is about 2 hours, and it is eliminated from the body within 24 hours after administration.

The drug is available in various formulations, including immediate-release, sustained-release, and extended-release formulations, with different pharmacokinetic profiles. The sustained-release and extended-release formulations of nifedipine provide a more gradual and prolonged release of the drug, allowing for once-daily dosing.

Adminstartion

Administration

nifedipine can be administered orally as immediate-release capsules or extended-release tablets. The immediate-release capsules are usually taken three times a day, while the extended-release tablets are taken once a day. The tablets should be taken whole with a glass of water and should not be crushed or chewed.

Patient Information Leaflet

Patient information leaflet

Generic Name: nifedipine

Pronounced: [ nye-FED-i-peen]

Why do we use nifedipine?

nifedipine is a drug that belongs to the class of calcium channel blockers. It is used in the management of preterm labor, which refers to contractions and cervical changes that occur before 37 weeks of pregnancy. nifedipine helps to relax the uterine muscles, which can reduce the frequency and intensity of contractions, and delay delivery. It is often used as a tocolytic agent to prevent or postpone preterm birth. However, it is important to note that nifedipine is not approved by the FDA for this indication, and its use is considered off-label. The decision to use nifedipine for preterm labor should be made by a healthcare professional based on individual patient factors and the risks and benefits of the medication.