Pharmacology · MU Sofia

38. Calcium channel blockers.

Covers calcium channel blockers, starting with how they inhibit calcium entry into cardiac and smooth muscle cells. It then sets out the dihydropyridine and non-dihydropyridine groups with their named drugs, followed by pharmacodynamic effects, half-lives and metabolism, side effects, drug interactions such as those with statins and grapefruit juice, clinical uses, and pregnancy and breastfeeding considerations.

Inside: 9 sections · 5 labelled pictures · 10 flashcards · 5 min

Topic 37 of 93 in the MU Sofia syllabus for Pharmacology (Medicine, Year 3). The free AceMed note covers it in 9 sections, about 729 words (5 min of reading), with 10 flashcards.

In this note

  1. Calcium Channel Blockers (CCBs)
  2. Classification
  3. Pharmacodynamics
  4. Pharmacokinetics
  5. Side Effects
  6. Drug Interactions
  7. Therapeutic Use
  8. Pregnancy and Breastfeeding
  9. Key Recap

Calcium Channel Blockers (CCBs)

Calcium channel blockers (CCBs) are a class of medications that inhibit the entry of calcium ions into cardiac and smooth muscle cells through voltage-gated calcium channels. By blocking these channels, CCBs reduce the availability of calcium for muscle contraction, leading to various effects in the cardiovascular system.

Classification

  1. 1. Dihydropyridines:
  • Amlodipine
  • Nifedipine
  • Felodipine
  • Nicardipine
  • Isradipine
  1. 2. Non-Dihydropyridines:
  • Verapamil
  • Diltiazem

Pharmacodynamics

Calcium channel blockers work by blocking L-type calcium channels in the cell membranes of cardiac and smooth muscle cells. This inhibition reduces the influx of calcium ions, which are essential for muscle contraction. The primary effects of CCBs include:

  • Vasodilation: Reduction in vascular smooth muscle tone, leading to relaxation and decreased blood pressure.
  • Decreased myocardial contractility: By inhibiting calcium entry, CCBs reduce the force of heart muscle contraction.
  • Slowed conduction through the AV node: This is particularly important in controlling heart rate, especially for certain arrhythmias.

Dihydropyridines predominantly affect vascular smooth muscle and are primarily used for their antihypertensive and anti-anginal effects. Non-dihydropyridines, such as verapamil and diltiazem, also affect cardiac tissue and are used for their antiarrhythmic properties, especially in controlling heart rate in conditions like atrial fibrillation.

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