III. Mechanism
- AV Node effects
- Reduces myocardial Oxygen Consumption
- Negative chronotropic effect
- Negative inotropic effect
- Reduces Systemic Vascular Resistance
- Results from vasodilatation of vascular Smooth Muscle
- Counters negative inotropic effect
- More negative hemodynamic effects than Diltiazem
- Coronary vasodilatation
IV. Contraindications
-
Wolff-Parkinson-White Syndrome with Atrial Fibrillation
- Paroxysmal accelerated ventricular response
- Risk of progression into Ventricular Fibrillation
-
Wide Complex Tachycardia (unless supraventricular)
- Risk of severe Hypotension
- May progress into Ventricular Fibrillation
- Verapamil ineffective against Ventricular Tachycardia
- Sinus Node or AV Node dysfunction without Pacemaker
- Severe Congestive Heart Failure
- Concurrent Intravenous Beta Blocker use
V. Indications
- Diltiazem is typically the preferred Non-Dihydropyridine Calcium Channel Blocker
- Paroxysmal Supraventricular Tachycardia (90% effective)
-
Supraventricular Tachycardia
- Terminates AV Node reentry Tachycardias
- Slows ventricular response to Atrial Fibrillation
- Verapamil is highly effective
- Used for acute treatment and prevention
-
Hypertension
- Consider Dihydropyridine Calcium Channel Blocker (e.g. Amlodipine) instead if Heart Rate control not needed
VI. Drug Interactions
- Increases Digitalis (Digoxin) level
- Beta Blocker (see contraindications above)
VII. Pharmacokinetics
- Peak effect seen within 3-5 minutes of bolus injection
VIII. Dosing
-
Supraventricular Tachycardia
- Adults
- Initial Dose: 2.5 to 5.0 mg IV bolus over 3 min
- Subsequent: 5 mg IV every 15 min (Max 30 mg total)
- Children (8-15 years old)
- Initial: 0.1 mg/kg up to 2.5 mg IV over 1-2 min
- Subsequent: 0.2 mg/kg up to 5 mg after 15 min
- Adults
-
Hypertension
- Regular: 80 mg PO tid (MAX 360 mg/day)
- Extended: 240 mg PO qd (MAX 480 mg/day)
IX. Precautions: Transient Hypotension
- Results from peripheral vasodilation
- Countered by Intravenous Calcium Injection
- Consider prophylactic pretreatment with Calcium
X. Adverse Effects
- See Calcium Channel Blocker
- Constipation (more than with Diltiazem)
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Related Studies
| verapamil (on 12/21/2022 at Medicaid.Gov Survey of pharmacy drug pricing) | ||
| VERAPAMIL 120 MG TABLET | Generic | $0.07 each |
| VERAPAMIL 40 MG TABLET | Generic | $0.13 each |
| VERAPAMIL 80 MG TABLET | Generic | $0.06 each |
| VERAPAMIL ER 120 MG CAPSULE | Generic | $1.14 each |
| VERAPAMIL ER 120 MG TABLET | Generic | $0.25 each |
| VERAPAMIL ER 180 MG CAPSULE | Generic | $1.14 each |
| VERAPAMIL ER 180 MG TABLET | Generic | $0.20 each |
| VERAPAMIL ER 240 MG CAPSULE | Generic | $1.30 each |
| VERAPAMIL ER 240 MG TABLET | Generic | $0.16 each |
| VERAPAMIL ER PM 100 MG CAPSULE | Generic | $4.29 each |
| VERAPAMIL ER PM 200 MG CAPSULE | Generic | $5.66 each |
| VERAPAMIL ER PM 300 MG CAPSULE | Generic | $8.37 each |
| VERAPAMIL SR 120 MG CAPSULE | Generic | $1.14 each |
| VERAPAMIL SR 180 MG CAPSULE | Generic | $1.14 each |
| VERAPAMIL SR 240 MG CAPSULE | Generic | $1.30 each |
| VERAPAMIL SR 360 MG CAPSULE | Generic | $4.52 each |