Calcium Channel Blocker

Aka: Calcium Channel Blocker

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II. Mechanism

  1. Cellular channel effects
    1. Effects slow Calcium channel activity (blocks voltage-gated L-type Calcium channels)
    2. Agents block both Calcium and Sodium inflow into cells during smooth muscle Action Potential phase
    3. Channels are present in cardiac and vascular Smooth Muscle
  2. Calcium Channel Blocker effects
    1. Myocardial relaxation (Non-Dihydropyridines primarily)
    2. Vascular Smooth Muscle relaxation
    3. Pancreatic B-islet cell inhibition
    4. Inhibits gastrointestinal Smooth Muscle propulsion (resulting in Constipation)

III. Types

  1. Dihydropyridine (e.g. Nifedipine, Amlodipine)
    1. Primary effects are on peripheral vasculature, resulting in vasodilation (with possible reflex increased Heart Rate)
    2. Amlodipine (Norvasc) is most commonly used and typically for Hypertension
    3. Nicardipine and Clevidipine are most commonly used in Hypertensive Emergency
  2. Non-Dihydropiridine (e.g. Verapamil, Diltiazem)
    1. Effect both peripheral vasculature and cardiac tissue, with a decrease in Heart Rate and Blood Pressure
    2. Diltiazem is most commonly used and typically used for Atrial Fibrillation Rate Control

IV. Adverse Effects: Myocardial Infarction

  1. Short Acting Calcium Channel Blockers
    1. Findings
      1. Myocardial Infarction Risk: 60% over Diuretics
      2. Higher dose confers >3x risk of lower dose
    2. References
      1. Psaty (1995) JAMA 274:620-5, 654-5 [PubMed]
      2. Furberg (1995) Circulation 92: 1326-31, 1068-73 [PubMed]
  2. Long acting Calcium Channel Blockers
    1. No increased cardiovascular disease risk
    2. Reference
      1. Alderman (1997) Lancet 349:594-8 [PubMed]

V. Adverse Effects: Bleeding risk

  1. Findings
    1. Higher Incidence of GI Hemorrhage in elderly
    2. Associated with Platelet aggregation inhibition
    3. Avoid in older patients if:
      1. Peptic Ulcer Disease
      2. Concurrent Aspirin use
      3. Perioperative
  2. References
    1. Pahor M (1996) Lancet 347:1061-5 [PubMed]
    2. Wagenknecht (1995) BMJ 310(6982):776-7 [PubMed]
    3. Zuccala (1997) BMJ 314:643-4 [PubMed]

VI. Adverse Effects: General

  1. Hypotension
  2. Flushing
  3. Nasal congestion
  4. Tachycardia
  5. Dizziness
  6. Nausea
  7. Nervousness
  8. Bowel changes
  9. Gingival Hyperplasia
  10. Eczematous Dermatitis (or other skin reactions)
    1. Occurs in up to 1% of patients on Calcium Channel Blockers
    2. Delayed onset at 3 months after starting Calcium Channel Blockers
    3. Joly (2007) J Invest Dermatol 127(12):2766-71 [PubMed]

VII. References

  1. (2022) Presc Lett 29(11): 64-5
  2. Yen (2015) Crit Dec Emerg Med 29(10): 18-23

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