Is amlodipine contraindicated in patients with complete heart block?

Amlodipine in Complete Heart Block

Amlodipine is not contraindicated in patients with complete heart block, as it has minimal to no effects on atrioventricular (AV) node conduction compared to other calcium channel blockers. 1

Pharmacological Properties of Amlodipine Relevant to Heart Block

• Amlodipine belongs to the dihydropyridine class of calcium channel blockers, which have predominant effects on peripheral arterial vasodilation with minimal effects on cardiac conduction 1
• According to FDA labeling, "Amlodipine does not change sinoatrial nodal function or atrioventricular conduction in intact animals or man" 2
• Unlike non-dihydropyridine calcium channel blockers (verapamil and diltiazem), which have prominent effects on AV and sinus node function, amlodipine has few or no AV or sinus node effects 1
• Electrophysiologic studies have shown that amlodipine does not significantly alter A-H and H-V conduction and sinus node recovery time after pacing 2

Clinical Considerations in Complete Heart Block

• In patients with complete heart block, the primary management should be focused on addressing the conduction disorder with appropriate pacing therapy 1
• A case report has documented bradyarrhythmias with amlodipine, but only in the setting of severe acute intoxication, not with therapeutic dosing 3
• When permanent pacing is required for complete heart block, amlodipine can be safely continued or initiated if needed for hypertension or angina management 1

Comparison with Other Calcium Channel Blockers

• Non-dihydropyridine calcium channel blockers (verapamil and diltiazem) have significant effects on AV nodal conduction and should be avoided in patients with heart block 1
• Verapamil specifically slows conduction through the AV node and is contraindicated if heart block is present 1
• For patients requiring calcium channel blocker therapy who have complete heart block, dihydropyridines like amlodipine are the preferred agents 1, 4

Cautions and Monitoring

• While not contraindicated, prudent clinical practice suggests monitoring patients with complete heart block when initiating any new medication, including amlodipine 1
• In patients with heart failure and reduced ejection fraction (HFrEF), calcium channel blockers including amlodipine are generally not recommended as routine treatment 1
• However, amlodipine may be considered for management of hypertension or ischemic heart disease in patients with heart failure as it is generally well tolerated 1

Special Situations

• In patients with complete heart block who require permanent pacing, amlodipine can be used safely for management of hypertension or angina 1
• If a patient with complete heart block develops new symptoms after starting amlodipine, clinical assessment should be performed, but this would not be expected from the drug's known pharmacological profile 2, 4

In summary, while non-dihydropyridine calcium channel blockers (verapamil, diltiazem) should be avoided in complete heart block, amlodipine is not contraindicated due to its minimal effects on cardiac conduction. The primary management for complete heart block remains appropriate pacing therapy.