Pharm

Mibefradil

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Mibefradil, T-Type Calcium Channel Blocker

  • Indications
  • Mechanism
  1. Blocks calcium influx at 2 types of calcium channels
    1. L-type (long-acting) channels
      1. Blocked by standard Calcium Channel Blockers
    2. T-type (transient) channels
      1. Blocked uniquely by Mibefradil
      2. Activated at lower voltages
      3. Present in:
        1. Vascular smooth muscle
        2. Myocardial conduction system
      4. Absent in
        1. Ventricular Myocardium
  2. Effect of Mibefradil
    1. Produces coronary and peripheral vasodilatation
    2. Does not result in reflex Tachycardia
  • Efficacy
  1. Antihypertensive
    1. More effective then Diltiazem
    2. As effective as Amlodipine and Nifedipine
    3. Synergistic effect with ACE Inhibitors
  2. Anti-Anginal
    1. Delays onset of ischemia during Exercise
    2. Increases Exercise tolerance
  • Contraindications
  • Drug Interactions
  1. Fatal arrhythmia risk with
    1. Terfenadine
    2. Astemizole
    3. Cisapride
  2. Increases levels of
    1. Tricyclic Antidepressant
    2. Cyclosporine
  • Adverse Effects
  1. Dizziness
  2. Fatigue
  3. Light headedness
  4. Peripheral Edema LESS common than others in class
  • Dosing
  1. 50 mg PO qd (up to 100 mg PO qd)