Lecture Notes: Calcium Channel Blockers - Diltiazem and Verapamil

Overview

• Diltiazem (Deltm) and Verapamil are medications in the calcium channel blocker class.
• Used primarily for their effects on the heart and blood vessels.

Memory Anchors

• Delta Zen Lounge for Diltiazem.
• Viper Meal for Verapamil.

Mechanism of Action

• Both drugs block calcium channels, particularly in cardiac and smooth muscle cells.
• Calcium channel blockers reduce the entry of calcium into cells, affecting muscle contraction and nerve signaling.

Drug Classification

• Class 4 Anti-arrhythmics
  • Treat abnormal heart rhythms by targeting calcium channels in the heart.
• Non-dihydropyridine calcium channel blockers.
  • Non-dihydropyridine: Different from dihydropyridine-type calcium channel blockers, mainly used as anti-arrhythmics.

Effects on the Body

• Vasodilation: Dilate blood vessels by blocking calcium channels in smooth muscle cells.
• Slow Heart Rate: Reduce calcium in heart cells, slowing heart rate.
• Weaken Heart Contractions: Lower calcium levels weaken the heart's ability to contract.
• Slow AV Node Conduction: Slow electrical conduction from the atria to the ventricles.

Clinical Uses

• Anti-arrhythmic Treatments:
  • Supraventricular Tachycardia (SVT): Fast rhythms above the ventricles.
  • Atrial Fibrillation (Afib): Irregular, rapid heartbeats due to chaotic electrical signals.
  • Atrial Flutter: Fast, regular atrial contractions.
• Angina and Myocardial Infarctions (MI): Increase blood flow to the heart by dilating coronary arteries.
• Hypertension: Lower blood pressure through vasodilation.

Side Effects

• Hypotension: Abnormally low blood pressure.
• Constipation: Due to slowed GI tract movement.
• Edema: Swelling caused by fluid retention, typically in the legs and feet.
• Heart Complications:
  • Heart Block: Slowed or blocked electrical signals from the atria to the ventricles.
  • Heart Failure: Weakened heart function leading to inadequate blood pumping.
• Dizziness: Often from orthostatic hypotension.
• Headache: Common side effect.
• Bradycardia: Abnormally slow heart rate.

Nursing Considerations

• Avoid Grapefruit Juice: Grapefruit juice interferes with the metabolism of the drugs, risking high levels of the drugs in the bloodstream.

Summary

• Diltiazem and Verapamil are Class 4 calcium channel blockers with significant effects on heart rate, blood pressure, and heart rhythm.
• Used to treat various cardiac conditions including SVT, Afib, atrial flutter, angina, MI, and hypertension.
• Monitor for a range of side effects, particularly those affecting the cardiovascular system and GI tract.
• Patients should avoid grapefruit juice to prevent complications.