Medicine & USMLE

DHP Calcium Channel Blockers

Cardio Drugs - Blood Pressure
  1. ACE Inhibitors
  2. Angiotensin II Receptor Blockers (ARBs)
  3. Beta Blockers: Mechanisms and Clinical Uses
  4. Beta Blockers: Side Effects
  5. DHP Calcium Channel Blockers
  6. Hydralazine
  7. Aliskiren
  8. Nitroprusside
  9. Alpha-1 Blockers
  10. Clonidine


Dihydropyridine calcium channel blockers are easy to recognize with their -dipine ending. Mechanistically, these drugs cause vasodilation, and dilate the arteries more than the veins. Clinically, they can be used to treat chest pain. They also treat hypertension by lowering blood pressure. Side effects include hypotension, reflex tachycardia, edema, facial flushing, gingival hyperplasia, dizziness, and headache. Patients taking calcium channel blockers should avoid grapefruit juice.

Key Points

  • Dihydropyridine Calcium Channel Blockers
    • Drug Name
      • -dipine Ending
        • Nifedipine
        • Amlodipine
        • Felodipine
        • Nicardipine
    • Clinical Use
      • Treats Angina (Chest Pain)
        • 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.
      • Treats Hypertension
    • Mechanism
      • Arterial Vasodilation
        • Dilates arteries more than veins
        • Blocks L-type calcium channels, leading to relaxation of the smooth vascular muscle in the arteries
    • Side Effects
      • Hypotension
        • Do not give if patient has low blood pressure
      • Reflex Tachycardia
        • When the blood pressure lowers quickly, the body naturally reacts by increasing the heart rate
      • Edema
        • Fluid and sodium retention lead to swelling in the extremities, especially the legs and ankles
      • Orthostatic Hypotension (Dizziness)
        • Sudden changes in movement can cause the blood pressure to drop, making the patient feel dizzy
        • Advise patients to change positions slowly to prevent dizziness
      • Flushing
      • Headache
      • Gingival Hyperplasia
        • Overgrowth of the gums
    • Nursing Considerations
      • Avoid Grapefruit Juice
        • Grapefruit juice interferes with how calcium channel blockers are metabolized in the body
        • A buildup of calcium channel blockers in the blood can lead to toxicity