Diltiazem

Aka: Diltiazem, Cardizem, Benzothiazapine

1. See Also
   1. Calcium Channel Blocker
   2. Calcium Channel Blocker Overdose
   3. Dihydropyridine Calcium Channel Blocker (e.g. Amlodipine, Nifedipine)
   4. Verapamil
   5. Mibefradil
2. Class
   1. Non-Dihydropyridine Calcium Channel Blocker
3. Mechanism
   1. AV Node effects
      1. Slow AV Node Conduction
      2. Prolong AV Node refractory period
   2. Less negative hemodynamic effects than Verapamil
      1. Potent negative chronotropic effect
      2. Minimal negative inotropic effect
      3. Diltiazem effects Left Ventricular Dysfunction less
   3. Coronary vasodilatation
4. Pharmacokinetics
   1. Onset in 2-7 minutes after IV infusion
5. Contraindications
   1. Wolff-Parkinson-White Syndrome with Atrial Fibrillation
      1. Paroxysmal accelerated ventricular response
      2. Risk of progression into Ventricular Fibrillation
   2. Wide Complex Tachycardia (unless supraventricular)
      1. Risk of severe Hypotension
      2. May progress into Ventricular Fibrillation
   3. Sinus Node or AV Node dysfunction without Pacemaker
      1. AV Block
      2. Sick Sinus Syndrome
   4. Severe Congestive Heart Failure
   5. Concurrent Intravenous Beta Blocker use
6. Indications
   1. Atrial Fibrillation with rapid ventricular response
      1. Highly effective at controlling ventricular rate
   2. Paroxysmal Supraventricular Tachycardia
      1. Less studied than Verapamil for PSVT
   3. Supraventricular Tachycardia
      1. Terminates AV Node reentry Tachycardias
   4. Hypertension
7. Dosing
   1. Rapid Atrial Fibrillation
      1. Initial: 0.25 mg/kg (to 20 mg) IV over 2 minutes
      2. Subsequent (after 15 min): 0.35 mg/kg (to 25 mg)
      3. Maintenance
         1. Intravenous: 5-15 mg/h titrated to Heart Rate
         2. Oral: 120-360 mg PO qd in divided doses
      4. Mnemonic: Rule of 15 for patient weight of 70 kg
         1. First: 15 mg IV over 2 minutes
         2. Next: IV infusion at 15 mg/hour
            1. Titrate infusion to ventricular rate
            2. Typical infusion: 5 to 15 mg per hour
   2. Paroxysmal Supraventricular Tachycardia
      1. Initial: 0.25 mg/kg IV over 2 min
      2. Subsequent (after 15 min): 0.35 mg/kg
   3. Hypertension
      1. Regular: 30 mg PO qid (MAX 360 mg/day)
      2. Extended: 180-240 mg qd (MAX 540 mg/day)