Can gabapentin (Neurontin) cause syncope?

Gabapentin and Syncope: Clinical Considerations

Gabapentin is not directly associated with syncope as a common adverse effect, but it can contribute to syncope through its neurological side effects including dizziness, somnolence, and altered mental status, particularly at higher doses. 1, 2

Mechanism and Risk Factors

• Gabapentin commonly causes dizziness (17% vs 7% in placebo) and somnolence (19% vs 9% in placebo), which can predispose patients to syncope, especially when changing positions 1

• Higher doses of gabapentin (≥600 mg/day) are associated with increased risk of falls, fractures, and altered mental status, which may be related to syncopal episodes 2

• Elderly patients are particularly vulnerable to medication-induced syncope due to age-related changes in baroreceptor response, heart rate response to orthostatic stress, and autonomic dysfunction 3

• Polypharmacy increases risk - concomitant use of other medications affecting cardiovascular function (diuretics, antihypertensives, antipsychotics, tricyclic antidepressants) can potentiate syncope risk 3

Clinical Presentation

• Syncope related to gabapentin may present with prodromal symptoms including:

  • Dizziness/lightheadedness
  • Visual disturbances (blurring, tunnel vision)
  • Weakness or fatigue
  • Somnolence
  • Ataxia or gait disturbance 3, 1

• Syncope is more likely to occur when transitioning from lying to standing position (orthostatic hypotension) 3

• The risk appears dose-dependent, with higher doses (≥1800 mg/day) potentially carrying greater risk 2, 4

Management Recommendations

• For patients experiencing syncope while on gabapentin:

  • Consider dose reduction, as adverse effects are often dose-related 1, 4
  • Start with lower doses (100-300 mg at bedtime) and titrate slowly to minimize adverse effects 3
  • Monitor for orthostatic blood pressure changes, especially in elderly patients 3

• If syncope occurs:

  • Evaluate for orthostatic hypotension by measuring blood pressure and heart rate in lying and standing positions 3
  • Consider medication review to identify potential drug interactions 3
  • Assess for underlying cardiac or neurological conditions that might be exacerbated by gabapentin 3

Special Considerations

• In rare cases, gabapentin has been reported to successfully treat certain forms of syncope, such as cough syncope and glossopharyngeal neuralgia with cardiac syncope 5, 6

• Patients with pre-existing autonomic dysfunction, cardiovascular disease, or elderly patients require closer monitoring when using gabapentin 3

• Gabapentin should be used with caution in patients with risk factors for falls, as it significantly increases this risk (RR 1.35,95% CI 1.28 to 1.44) 2

• Discontinuation should be gradual to prevent withdrawal symptoms, which could potentially include cardiovascular effects 1

Prevention Strategies

• Advise patients not to drive or operate complex machinery until they have gained sufficient experience with gabapentin to assess whether it impairs their abilities 1

• Educate patients about potential orthostatic symptoms and to change positions slowly, especially when rising from lying or sitting positions 3

• Consider starting with lower doses in elderly patients or those with multiple comorbidities 3, 4

• Monitor patients for signs of CNS depression, especially when gabapentin is used with other sedative medications 1