Can gabapentin (anticonvulsant medication) affect one's ability to drive safely?

Gabapentin and Driving Safety

Gabapentin significantly impairs driving ability, especially during initial treatment, and patients should not drive until they have gained sufficient experience to assess whether the medication affects their driving competence. 1

Effects of Gabapentin on Driving Performance

Gabapentin causes several side effects that directly impact driving ability:

• Somnolence/sedation: Occurs in 19% of patients taking gabapentin versus 9% in placebo groups 1
• Dizziness: Reported in 17% of gabapentin users versus 7% in placebo groups 1
• Ataxia (lack of coordination): Present in 13% of gabapentin users versus 6% in placebo groups 1
• Visual disturbances: Including blurred vision 2

These side effects are particularly pronounced during:

1. Initial treatment phases
2. Dose adjustments
3. When combined with other CNS depressants

Driving Impairment Evidence

The FDA label explicitly warns that:

• Driving performance studies with gabapentin enacarbil (a prodrug of gabapentin) indicate significant driving impairment 1
• Patients' ability to assess their own driving competence and degree of somnolence can be imperfect 1

Recent forensic evidence shows concerning patterns:

• A 2024 review of 108,000 gabapentin-positive driving under the influence cases found 7.9% positivity rate between 2020-2022 2
• Half of the case histories involving gabapentin alone resulted in crashes where the driver was at fault 2
• In Washington State, gabapentin was detected in impaired driving cases with blood concentrations ranging from <2.0 to 24.7 mg/L 3

Risk Factors for Increased Impairment

The risk of driving impairment is significantly higher with:

1. Higher doses: Clear dose-response relationship with risk of falls or altered mental status, particularly at doses ≥600 mg/day 4
2. Concomitant medications: 94% of gabapentin-related impaired driving cases involved combination with other drugs, most commonly opioids (64% of cases) 2
3. Initial treatment period: The FDA label notes that the duration of driving impairment after starting therapy is unknown 1
4. Elderly patients: Higher risk of adverse effects including drowsiness 5

Recommendations for Patients on Gabapentin

1. Initial treatment phase:

   • Do not drive during initial treatment with gabapentin
   • Avoid operating heavy machinery or performing tasks requiring alertness

2. Ongoing treatment:

   • Do not drive until you have gained sufficient experience to assess whether gabapentin impairs your ability 1
   • Be aware that your own assessment of your driving ability may be imperfect 1

3. Risk reduction strategies:

   • Avoid alcohol and other CNS depressants while taking gabapentin 1
   • Take particular caution if dose is ≥600 mg/day 4
   • Be aware that gabapentin can cause falls and altered mental status even with long-term use 4

Special Considerations

While some antiseizure medications show diminished effects on driving with continued use 6, gabapentin specifically continues to present risks. Unlike some other antiseizure medications where chronic monotherapy shows minimal driving impairment, gabapentin's FDA label explicitly warns about significant driving impairment 1.

The risk of adverse events is particularly concerning as a 2020 study of 571,718 US Veterans found gabapentin was associated with increased risk of falls/fractures (RR 1.35) and altered mental status (RR 1.12) compared to matched controls, with a clear dose-response relationship 4.