Generic Name: Nifedipine.

Trade Name    : Epilat.

Drug Class      : Calcium Channel Blockers.

Forms of The Drug

  1. Tablet, Extended Release: 30mg, 60mg, 90mg.
  2. Capsule: 10mg, 20mg.

Mechanism of Action

Nifedipine belongs to the dihydropyridine class of calcium channel blockers. Its mechanism of action can be summarized as follows:

  1. Inhibition of Calcium Influx: Nifedipine primarily works by inhibiting the influx of calcium ions into cardiac and smooth muscle cells. Calcium ions play a crucial role in muscle contraction, including the heart, and in the regulation of blood vessel tone. By blocking calcium channels, nifedipine reduces the amount of calcium available to enter these cells during each heartbeat.
  2. Cardiac Effects: In the heart, nifedipine targets calcium channels in the cardiac muscle cells, particularly those in the myocardium (heart muscle). By blocking these channels, it reduces the entry of calcium ions into the cells. This has several effects on the heart:
    • Reduction in Contractility: Nifedipine decreases the force of cardiac muscle contraction. As a result, it reduces the workload of the heart and decreases the oxygen demand of the myocardium. This can be helpful in managing angina (chest pain) and certain types of abnormal heart rhythms.
    • Vasodilation: Nifedipine’s vasodilatory effect can help reduce afterload, which is the resistance the heart must overcome to pump blood out to the body. This can be beneficial for individuals with high blood pressure and heart conditions.
  3. Vasodilation: Nifedipine primarily affects the smooth muscle cells in the walls of blood vessels, particularly the arterioles (small arteries). By inhibiting the influx of calcium into these cells, nifedipine causes relaxation and dilation of the blood vessels. This results in a decrease in systemic vascular resistance, which, in turn, lowers blood pressure. The reduction in afterload reduces the workload on the heart and can be beneficial in managing high blood pressure and certain cardiovascular conditions.
  4. Anti-Anginal Effects: Nifedipine is particularly effective in the management of angina pectoris, a condition characterized by chest pain or discomfort due to reduced blood flow to the heart muscle. By dilating coronary arteries and reducing the heart’s workload, nifedipine can alleviate angina symptoms.

Indications

  1. Hypertension (High Blood Pressure).
  2. Angina pectoris.
  3. Raynaud’s phenomenon.
  4. Vasospastic angina.
  5. Hypertrophic cardiomyopathy.
  6. Esophageal hypertension.
  7. Preterm labor.
  8. Reynaud’s disease.
  9. Atrial fibrillation or atrial flutter.

Contraindications

  1. Hypersensitivity.
  2. Severe hypotension.
  3. Cardiogenic shock.
  4. Heart failure.
  5. Aortic stenosis.
  6. Second- or Third-Degree Atrioventricular (AV) Block.
  7. Concomitant use of strong CYP3A4 inhibitors.
  8. Previous serious hypersensitivity reaction.
  9. Grapefruit juice.

Side Effects

  1. Peripheral edema (10-30%).
  2. Dizziness (23-27%).
  3. Flushing (23-27%).
  4. Headache (10-23%).
  5. Heartburn (11%).
  6. Nausea (11%).
  7. Muscle cramps (8%).
  8. Mood change (7%).
  9. Nervousness (7%).
  10. Cough (6%).
  11. Dyspnea (6%).
  12. Palpitations (6%).
  13. Wheezing (6%).
  14. Hypotension, transient (5%).
  15. Urticaria (2%).
  16. Pruritus (2%).
  17. Constipation (<2%).
  18. Chest pain (<2%).

Drug Interaction

Drugs that can interact with the drug.

  1. Beta-Blockers: Combining Nifedipine with beta-blockers (e.g., propranolol, metoprolol).
  2. Digoxin.
  3. Lithium.
  4. Cyclosporine.
  5. Statins: Nifedipine may increase blood levels of certain statin drugs (e.g., atorvastatin, simvastatin).
  6. Anticoagulants (Warfarin).
  7. CYP3A4 Inhibitors: Medications that inhibit the CYP3A4 enzyme, such as ketoconazole, itraconazole, and erythromycin.
  8. Other Antihypertensive Agents: When multiple antihypertensive agents (e.g., ACE inhibitors, angiotensin receptor blockers, diuretics).
  9. Antifungals: Azole antifungal medications (e.g., ketoconazole, itraconazole)
  10. Grapefruit juice.

Precautions

  1. Pregnancy: Category C
  2. Lactation: Nifedipine, a calcium channel blocker, can pass into breast milk when taken by lactating mothers. While the transfer of Nifedipine to breast milk is relatively low, it is essential for nursing mothers and their healthcare providers to consider the potential effects and risks of Nifedipine during lactation.

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