Can gabapentin (Neurontin) cause bradycardia?

Can Gabapentin Cause Bradycardia?

Yes, gabapentin can cause bradycardia, particularly in susceptible individuals, as demonstrated by recent animal studies showing that both acute and chronic gabapentin treatment significantly decreased heart rate in rats.

Evidence for Gabapentin-Induced Bradycardia

Mechanism and Animal Studies

Recent research provides the strongest evidence for gabapentin's potential to cause bradycardia:

• A 2023 study demonstrated that both acute and chronic gabapentin administration in rats resulted in significant bradycardia 1
• The same study found that gabapentin treatment led to:
  • Decreased blood pressure
  • Reduced heart rate
  • Impaired left ventricular function
  • Alterations in calcium signaling pathways in cardiac tissue 1

Clinical Evidence and Case Reports

While clinical guidelines don't specifically list bradycardia as a common adverse effect of gabapentin, there is evidence suggesting cardiovascular effects:

• A 2023 case report documented atrial fibrillation in a young patient shortly after starting gabapentin therapy 2
• Another case report described a patient who developed dystonia after gabapentin treatment that had previously experienced bradycardia with propranolol 3
• A 2011 case report described possible heart failure associated with pregabalin (a similar gabapentinoid) use 4

Cardiovascular Risk Profile of Gabapentinoids

A 2022 large-scale retrospective cohort study examining cardiovascular risks in diabetic neuropathy patients found:

• Both gabapentin and pregabalin were associated with increased risk of various cardiovascular events
• The study included 210,064 patients with diabetic neuropathy
• Significant associations were found between gabapentin use and heart failure, myocardial infarction, peripheral vascular disease, stroke, and thromboembolic events 5

Comparison with Other Medications Known to Cause Bradycardia

For context, several medications are well-established to cause bradycardia:

• Dexmedetomidine is associated with risk of sedation, hypotension, and bradycardia 6
• Ivabradine carries a risk of bradycardia, particularly when combined with other drugs that affect heart rate 6
• Beta-blockers, verapamil, diltiazem, and digoxin are known to cause bradycardia as common pharmacological effects 6

Clinical Implications and Recommendations

When considering gabapentin therapy:

1. Exercise caution in patients with:

   • Pre-existing cardiac conduction disorders
   • Patients on other medications that can cause bradycardia
   • Elderly patients or those with multiple comorbidities

2. Monitor for symptoms of bradycardia:

   • Dizziness
   • Fatigue
   • Syncope or near-syncope
   • Weakness

3. Consider cardiac monitoring:

   • Baseline ECG before starting therapy in high-risk patients
   • Follow-up ECG if symptoms develop
   • Heart rate monitoring in susceptible individuals

4. Dose considerations:

   • Start with lower doses in patients with cardiac risk factors
   • Titrate slowly while monitoring for cardiovascular effects

Conclusion

While not as commonly recognized as with medications like beta-blockers or calcium channel blockers, the evidence suggests gabapentin can cause bradycardia, particularly in animal models. The clinical significance may vary between individuals, but healthcare providers should be aware of this potential adverse effect, especially when prescribing gabapentin to patients with pre-existing cardiac conditions or those taking other medications that affect heart rate.