Is gabapentin (Neurontin) contraindicated in patients with atrioventricular (AV) block?

Gabapentin Use in Patients with Heart Block

Gabapentin is not specifically contraindicated in patients with atrioventricular (AV) block, but should be used with caution and close monitoring due to rare reports of cardiac conduction abnormalities.

Cardiac Effects of Gabapentin

• Gabapentin is not listed as contraindicated in heart block in major cardiovascular guidelines 1
• There have been isolated case reports of cardiac effects with gabapentin, including:
  • Complete AV block associated with pregabalin (a similar medication) 2
  • Atrial fibrillation induced by gabapentin in a young patient 3
  • Possible heart failure associated with pregabalin and gabapentin use 4
  • A rare case of gabapentin-induced cardiomyopathy 5

Risk Assessment and Monitoring

• Patients with pre-existing cardiac conduction disorders should be monitored more closely when starting gabapentin therapy 2, 6
• The mechanism of potential cardiac effects may be related to gabapentin's effects on calcium channels, which could theoretically affect cardiac conduction 2, 4
• For patients with heart block:
  • Baseline ECG documentation of the degree of heart block is recommended before starting therapy 6
  • Regular follow-up ECGs should be considered to monitor for worsening of conduction abnormalities 6

Management Considerations

• For patients with AV block who require gabapentin:
  • Start with lower doses and titrate slowly while monitoring for signs of worsening conduction 2, 4
  • Consider alternative medications for neuropathic pain if the patient has high-grade AV block 4
  • Be particularly cautious in elderly patients or those with multiple cardiac risk factors 4, 6

Special Situations

• In patients with heart block who are also taking other medications that affect cardiac conduction:
  • Avoid combining gabapentin with other medications that can worsen AV block, such as beta blockers, calcium channel blockers, or amiodarone 1
  • For patients with heart failure and heart block, monitor closely for signs of worsening heart failure when using gabapentin 4

Clinical Approach

• If a patient on gabapentin develops new or worsening heart block:
  • Consider temporary discontinuation of gabapentin to determine if it is contributing to the conduction abnormality 2, 6
  • If heart block resolves after discontinuation and gabapentin is still needed, consider restarting at a lower dose with careful monitoring 4
  • For persistent high-grade AV block, permanent pacing may be necessary, especially in elderly patients 6

While there is no absolute contraindication to using gabapentin in patients with heart block, the limited case reports of cardiac effects suggest caution is warranted, particularly in patients with pre-existing high-grade conduction abnormalities.