Medicine & USMLE

DHP Calcium Channel Blockers (Old)

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DHP calcium channel blockers consist of medications that end in “-dipine”, including amlodipine, nifedipine, and felodipine. These drugs work by causing arterial vasodilation, which has the overall effect of reducing blood pressure. Clinically, these drugs are used to treat hypertension and angina. Side effects include peripheral edema, flushing, reflex tachycardia, and headache. Patients taking calcium channel blockers should avoid grapefruit juice.

Key Points

  • Dihydropyridines (DHP) Calcium Channel Blockers
    • Key Drugs
      • “-dipine”
      • Amlodipine
      • Nifedipine
      • Felodipine
    • Mechanism
      • Block calcium channels in the vascular smooth muscle, leading to arterial vasodilation in the peripheral and coronary arteries.
    • Clinical Use
      • Hypertension
      • Angina
        • Angina is caused by lack of blood flow to the cardiac muscle. Relaxation of the coronary arteries allows for more blood flow (more oxygen) to reach the cardiac muscle and decreases chest pain.
      • Raynaud's Disease
    • SE and AR
      • Effects due to vasodilation
        • Peripheral edema
        • Flushing
        • Headache
      • Hypotension
        • Reflex tachycardia
        • Dizziness (orthostatic hypotension)
      • Gingival hyperplasia
      • Avoid grapefruit juice
        • Increases the amount of nifedipine in the body by inhibiting liver enzymes responsible for drug breakdown
        • May lead to severe hypotension