Indications

• Angina (see Coronary Artery Disease)
• Cluster Headache Prophylaxis
• Hypertension (see Hypertension)
• Migraine Prophylaxis (see Migraines)
• Rate Control of AV Nodal-Mediated Arrhythmias
  • Atrial Fibrillation with Rapid Ventricular Response (see Atrial Fibrillation)
  • Supraventricular Tachycardia (SVT) with Rapid Ventricular Response (see Supraventricular Tachycardia)

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Contraindications

Atrioventricular Heart Blocks

• First Degree Atrioventricular Block (First Degree Heart Block) (see First Degree Atrioventricular Block): with P-R interval ≥0.24 sec
• Second Degree Atrioventricular Block-Mobitz Type I (Wenckebach) (see Second Degree Atrioventricular Block-Mobitz Type I)
• Second Degree Atrioventricular Block-Mobitz Type II (see Second Degree Atrioventricular Block-Mobitz Type II)
• Third Degree Atrioventricular Block (Third Degree Heart Block, Complete Heart Block) (see Third Degree Atrioventricular Block)

Hypotension (see Hypotension)

• Verapamil May Exacerbate Hypotension

Sinus Bradycardia (see Sinus Bradycardia)

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Pharmacology

• Non-Dihydropyridines (Phenylalkylamine) Calcium Channel Blocker (see Calcium Channel Blockers)

Physiologic Effects

• Atrioventricular Nodal Blockade: since calcium channels are especially concentrated in the sinoatrial and atrioventricular nodes within the heart
• Class IV Anti-Arrhythmic
• Coronary Vasodilation: via calcium channels located within vascular smooth muscle
• Decreased Myocardial Oxygen Consumption
• Minimal Systemic Vasodilation: via calcium channels located within vascular smooth muscle
  • Verapamil is relatively selective for the myocardium (compared to the dihydropyridine calcium channel blockers) and it therefore, causes less reflex tachycardia than the dihydropyridine calcium channel blockers
• Negative Inotropy

Metabolism

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Administration

• PO:
• IV:

Dose Adjustment

• Hepatic
• Renal

Use During Pregnancy (see Pregnancy)

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Use During Breast Feeding

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Adverse Effects

Cardiovascular Adverse Effects

Atrioventricular Heart Blocks

• First Degree Atrioventricular Block (First Degree Heart Block) (see First Degree Atrioventricular Block)
• Second Degree Atrioventricular Block-Mobitz Type I (Wenckebach) (see Second Degree Atrioventricular Block-Mobitz Type I)
• Second Degree Atrioventricular Block-Mobitz Type II (see Second Degree Atrioventricular Block-Mobitz Type II)
• Third Degree Atrioventricular Block (Third Degree Heart Block, Complete Heart Block) (see Third Degree Atrioventricular Block)

Sinus Bradycardia (see Sinus Bradycardia)

• May Occur

Hypotension (see Hypotension)

• Physiology: class effect (common to all calcium channel blockers)

Dermatologic Adverse Effects

• Facial Flushing (see Flushing)

Endocrinologic Adverse Effects

• Galactorrhea (see Galactorrhea)

Gastrointestinal Adverse Effects

• Constipation/Ileus (see Constipation and Ileus)
• Nausea (see Nausea and Vomiting)

Hematologic Adverse Effects

• Ecchymosis

Neurologic Adverse Effects

• Dizziness (see Dizziness)
• Fatigue (see Fatigue)
• Headache (see Headache)

Otolaryngologic Adverse Effects

Gingival Hypertrophy (see Gingival Hypertrophy)

• Physiology: class effect (observed with other calcium channel blockers, as well)

Renal Adverse Effects

• Increased Urination

Rheumatologic Adverse Effects

• Peripheral Edema (see Peripheral Edema)

Other Adverse Effects

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Calcium Channel Blocker Intoxication

• See Calcium Channel Blockers

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References

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