Mibefradil

Aka: Mibefradil, T-Type Calcium Channel Blocker

1. See Also
   1. Calcium Channel Blocker
   2. Calcium Channel Blocker Overdose
   3. Dihydropyridine Calcium Channel Blocker (e.g. Amlodipine, Nifedipine)
   4. Diltiazem
   5. Verapamil
2. Indications
   1. Chronic Stable Angina
   2. Hypertension
3. 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
4. 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
5. Contraindications
   1. Sick Sinus Syndrome
   2. AV Block without a Pacemaker
6. Drug Interactions
   1. Fatal arrhythmia risk with
      1. Terfenadine
      2. Astemizole
      3. Cisapride
   2. Increases levels of
      1. Tricyclic Antidepressant
      2. Cyclosporine
7. Adverse Effects
   1. Dizziness
   2. Fatigue
   3. Light headedness
   4. Peripheral Edema LESS common than others in class
8. Dosing
   1. 50 mg PO qd (up to 100 mg PO qd)
9. References
   1. (1997) Med Lett Drugs Ther 39:103-5 [PubMed]